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PubMed1998

Fertilization promoting peptide: an important regulator of sperm function in vivo?

Fertilization promoting peptide (FPP; pGlu-Glu-ProNH2), a tripeptide structurally related to thyrotrophin releasing hormone, is produced by the prostate gland and released into seminal plasma. Recent studies carried out in vitro have revealed that FPP elicits biologically important responses in both mouse and human spermatozoa. In the presence of physiological concentrations of FPP (50-100 nmol l(-1)), uncapacitated spermatozoa undergo accelerated capacitation and so become potentially fertilizing more quickly, while capacitated spermatozoa are inhibited from undergoing spontaneous acrosomal exocytosis, an event that would make them non-fertilizing. In vivo, these responses would be very important since relatively few spermatozoa reach the site of fertilization; FPP could help to ensure that these were potentially fertilizing cells. A putative receptor (TCP-11) for FPP has been identified in mice. The gene for TCP-11 (which has a human homologue) maps to the t-complex, a region known to contain genes affecting male fertility. Current evidence indicates that FPP and TCP-11 act by modulating the activity of adenylyl cyclase and hence production of cAMP, a signal transduction pathway shown to be important in the acquisition of fertilizing ability. These results suggest that FPP plays an important role in normal fertility and that insufficient FPP could reduce fertility. Prostatic dysfunction can lead to decreased synthesis of FPP and increased synthesis of FPP-related peptides with reduced biological activity, both of which could compromise fertility in vivo. Given that 'male factor' infertility is a common contributor to subfertility in couples, it may prove possible to develop new therapeutic treatments, for at least some males, using FPP. In addition, this ligand-receptor pair could provide a novel target for male contraception.

Animals↗
PubMed1993

Ultrastructural characteristics of in vivo and in vitro fertilization in the grey short-tailed opossum, Monodelphis domestica.

To establish the mode of fertilization in a marsupial, a morphological investigation was made of the gametes of the South American grey short-tailed opossum. Monodelphis domestica, at the time of fertilization in vivo and in vitro. Oestrus was induced in females by the introduction of an unfamiliar male. To obtain oocytes recently fertilized in vivo, females were killed 18-24 hours after the first mating and the region of the oviduct containing eggs excised and fixed. Unfertilized mature oocytes were recovered from ovarian follicles 15-18 hours after first mating and fertilized in vitro with cauda epididymal spermatozoa in a modified MEM medium supplemented with bovine serum albumin at 37 degrees C in 5% CO2 in air. Following sperm-egg binding and fertilization, oocytes were fixed and prepared for light and electron microscopy. Spermatozoa unpaired prior to fertilization in vivo and in vitro and single spermatozoa bound to the zona surface by their plasmalemma overlying the acrosome on the dorsal face of the sperm head. The acrosome reaction was only observed at the zona surface (suggesting that it may be induced by zona components) and involved a vesiculation of sperm plasma and acrosomal membranes over the main body of the acrosome but not over the narrow, marginal region which persisted after the acrosome reaction was complete. Sperm penetration of the zona pellucida caused a large breach in the zona and the dispersal of perivitelline material. The fusion of the spermatozoon with the oolemma occurred first over the marginal acrosomal region and was accompanied by a fertilization cone which protruded through the zona penetration hole. Activation of the egg was characterized by the release of material from vesicles in the peripheral cytoplasm and extrusion of the second polar body. The mode of fertilization in Monodelphis was compared with what is known in other marsupials (New World and Australian) and eutherian (placental) mammals. It was concluded that the general features of the acrosome reaction and sperm-egg fusion may be essentially similar in both groups and that an evolutionary schism did not occur following the development of the eutherian mode of fertilization.

Acrosome↗
PubMed1991

Impact of a second insemination on the results of an in vitro fertilization-embryo transfer (IVF-ET) program.

In an attempt to increase the fertilization and pregnancy rates in our program, a second insemination was carried out when the first insemination yielded fewer than two fertilized oocytes. One hundred eighty consecutive patients were studied retrospectively and thirty-four required second insemination, 35% of them by donor semen. Fifty-five and nine-tenths percent of the patients had at least one fertilized oocyte for embryo transfer, but only 21.9% of the oocytes exposed to a second insemination were fertilized. No pregnancy resulted from the transfer of oocytes fertilized by the second insemination. There were no significant correlations between the success of fertilization after a second insemination and the number of oocytes retrieved, the protocol for the induction of superovulation, or the age of the female patient. Considering that the first insemination was done at a variable time after oocyte retrieval to allow oocyte maturation, we expected all oocytes to be mature at the time of first insemination and we considered the possibility of delayed fertilization as negligible since second insemination was done at least 24-30 hr after oocyte retrieval. Even though a second insemination provides further hope for the patient, by yielding additional fertilized oocytes for embryo transfer, its main value is that it may provide additional information about male fertility.

Adult↗
PubMed1995

Successful use of pentoxifylline in male-factor infertility and previous failure of in vitro fertilization: a prospective randomized study.

OBJECTIVE: Our objective was to determine whether the use of pentoxifylline (PF) would improve the in vitro fertilization (IVF) rate and outcome in couples with male factor infertility and previous failure of fertilization in vitro. DESIGN: This prospective randomized controlled study was conducted in an assisted conception unit. MATERIALS AND METHODS: Forty-nine couples with previous failed fertilization in vitro attributable to male factor or male-factor infertility without previous IVF were recruited for the study. Controlled ovarian hyperstimulation was performed using a combination of gonadotropin releasing hormone agonist and human menopausal gonadotropin. Oocytes of the same grade and maturity were inseminated with spermatozoa treated with PF or control spermatozoa. A maximum of three embryos was replaced after 48 hr and all other embryos were cryopreserved. Pregnancy outcome was followed up and evidence of fetal or neonatal anomalies reported. RESULTS: A significantly higher fertilization rate occurred in the group where oocytes were inseminated with spermatozoa treated with PF compared with controls (56.3 versus 30.7%; P < 0.05). Fertilization occurred in 45 of the 49 cycles (92%). In seven cycles, only the oocytes that were inseminated with spermatozoa treated with PF fertilized, in contrast to only one cycle where the oocytes inseminated with control sperm fertilized (P < 0.05). Fifty-seven PF and 31 control embryos were replaced and 11 clinical pregnancies occurred. Three of the pregnancies occurred in the seven cycles in which only PF embryos were replaced, one in the single cycle where control embryos were replaced and seven from the 37 cycles in which both PF and control embryos were replaced. There was no evidence of congenital malformations in any of the offsprings resulting from this study. CONCLUSION: This study suggests that PF improves the fertilization rate and outcome in couples with male factor infertility and poor fertilization rates. This study does not suggest any increase in teratogenicity or evidence of congenital malformations in pregnancies following IVF cycles where PF was used.

Adult↗
PubMed1993

Presence of sperm in the perivitelline space predicts fertilization rate after partial zona dissection.

OBJECTIVE: To examine the association of the number of spermatozoa present in the perivitelline space and sperm parameters with fertilization after partial zona dissection in male factor patients. DESIGN: Partial zona dissection was applied in 62 couples (84 cycles). A total of 524 oocytes underwent partial zona dissection (1/8 of the zona circumference) (partial zona dissection group) and 171 sibling oocytes were not manipulated (control group). A total of 326 manipulated oocytes were examined for the presence of spermatozoa in the perivitelline space. SETTING: University-based in vitro fertilization (IVF) program. PATIENTS: Fifty-four (87%) couples had at least one complete failure of fertilization, and 8 (13%) couples had low fertilization rate (< 10%) in previous routine IVF attempts. MAIN OUTCOME MEASURES: Fertilization rate, cleavage rate, and the number of spermatozoa present in the perivitelline space after partial zona dissection. RESULTS: Monospermic and polyspermic fertilization rates were 22.3% and 6.7% in the partial zona dissection oocytes and 8.8% and 0.6% in the nonmanipulated oocytes, respectively. The cleavage rate was similar in the partial zona dissection and control group (69.2% and 66.6%, respectively). A total of 81 partial zona dissection embryos and 10 nonmanipulated embryos were transferred to the uterus of 34 women (39 cycles), resulting in four pregnancies. In 46% (18 of 39) of the patients who had both partial zona dissection and control oocytes, only the manipulated oocytes fertilized. In only 48.8% of partial zona dissection oocytes, spermatozoa were detected in the perivitelline space; in this group of oocytes the fertilization rate was 56.6%. Sperm count and morphology were not clearly correlated with the outcome of partial zona dissection. CONCLUSIONS: The partial zona dissection technique enhances fertilization of subfertile sperm. However, the low efficiency of the procedure, apart from being associated with a high polyspermic rate, is related to the failure of sperm to traverse the slit in the zona pellucida in approximately one half of the manipulated oocytes.

Adult↗
PubMed1997

In vitro fertilization rate of mouse oocytes with spermatozoa from the F1 offspring of males irradiated with 1.0 Gy 137Cs gamma-rays.

Previous studies suggest that the spermatozoa from acutely irradiated male mice exhibit a reduced fertilization rate in vitro with the maximum decrease occurring for spermatozoa produced 6 weeks after irradiation (Y. Matsuda et al., Mutation Res. 142 (1985) 59-63). We have found that spermatozoa from unirradiated F1 males conceived 6 weeks after paternal F0 irradiation also exhibit a significantly reduced fertilization rate in vitro. After acute 137Cs gamma-irradiation yielding an absorbed dose of 1.0 Gy, adult CD1 F0 male mice were mated at weekly intervals with unirradiated female CD1 mice. Unirradiated adult males from F1 litters conceived 5 and 6 weeks after paternal F0 irradiation were allowed to mature. Their epididymal spermatozoa were evaluated for in vitro fertilization rates using oocytes from unirradiated 8-12-week-old CD1 females. The mean fertilization rate for spermatozoa from F1 males conceived 5 weeks after paternal F0 irradiation (80.74 +/- 15.74 SD %, n = 5) did not differ significantly from the control fertilization rate (89.40 +/- 10.94 SD %, n = 8). However, the fertilization rate for spermatozoa from F1 males conceived 6 weeks after paternal F0 irradiation (56.14 +/- 21.93 SD %, n = 5) was significantly less than the fertilization rate for control spermatozoa (p < 0.006) or for that of the F1 males conceived 5 weeks after paternal F0 irradiation (p < 0.04). These data suggest that spermatozoa obtained 6 weeks after paternal F0 irradiation can transmit a decrease in fertilization rate to the F1 generation males as well as exhibit decreased fertilization rate themselves when tested directly in vitro.

Animals↗
PubMed1999

Relationship between bull field fertility and in vitro embryo production using sperm preparation methods with and without somatic cell co-culture.

Experiments were designed to compare rates of embryonic development following oocyte exposure to cryopreserved spermatozoa from bulls of varying proven fertility, utilizing 3 different sperm preparation methods prior to oocyte introduction. These included 1) sperm co-culture with bovine oviductal epithelial cells (BOEC); 2) sperm co-culture with buffalo rat liver cells (BRLC); or 3) control culture in a routine, cell-free culture system. Semen from 9 bulls was classified by lifetime 60- to 90-d nonreturn rates as having either (mean +/- SEM) high (n=3) 73.2 +/- 3a, medium (n=3) 70.3 +/- 2b or low (n=3) 65.8 +/- 3c field fertility ((ac)p< 0.01; (bc)p< 0.05). There was no difference in embryo cleavage rates for spermatozoa from the high (58 +/- 18%), medium (57 +/-23%) or low (57 +/- 18%) fertility groups. Development to morula or beyond of oocytes fertilized with high (53 +/- 30%) or low (58 +/- 27%) fertility semen tended (P<0.10) to be higher than of those fertilized with medium fertility (33 +/- 28%) semen. This lack of relationship between in vivo fertility and in vitro embryo outcome was consistent across all sperm preparation methods. Therefore, pooled data were used to evaluate the effect of sperm preparation on embryo outcome. There was no difference in embryo cleavage rates between BOEC monolayers (51 +/- 22%), BRLC monolayers (60 +/- 20%) and the cell-free controls (60 +/- 17%). Subsequent embryonic development to compact morula and beyond was higher (P<0.01) with the BRLC monolayer treatment (61 +/- 28%) than with the BOEC monolayers (42 +/- 33%) or control culture (39 +/- 24%). In conclusion, these studies suggest that there is no predictive relationship between bull field fertility (in the ranges evaluated here) and in vitro embryo cleavage or development rates. However, oocytes inseminated with sperm cells co-cultured on BRLC monolayers develop to the morula stage or beyond at a higher rate than oocytes inseminated with spermatozoa from the BOEC or cell-free system.

Animals↗
PubMed1999

Prediction of bull fertility by combined in vitro assessments of frozen-thawed semen from young dairy bulls entering an AI-programme.

In the present study, we assessed the degree to which various bull sperm traits, including the ability to bind to homologous zona pellucidae (ZP) and to fertilize in vitro, were related to field fertility after AI as 56d-non-return rates (56d-NRR based upon 8620 AIs) with frozen-thawed semen from 12 Swedish Red and White young (11-13 months) bulls (3 freezing batches/bull, 1-2 consecutive ejaculates/batch), entering a national breeding program and housed at two AI-bull stations. Significant (p < 0.01) correlations among in vitro tests were found for swim-up separated spermatozoa (concentration and concentration of motile spermatozoa) with the ZP-binding assay (ZBA, r = 0.72 and r = 0.73, respectively) and blastocyst rates (r = 0.79 and r = 0.79, respectively). A strong correlation was found between cleavage and blastocyst rates (r = 0.81, p < 0.01). Whereas bull station influenced (p < 0.05-0.001) all these variables, bull only affected (p < 0.05) ZBA and cleavage. There was no significant difference in 56d-NRRs (p > 0.05, range 62-67.2%) among bulls, once the absolute NRRs had been corrected for season, area and parity. Neither bull, batch nor station had a significant effect on field fertility (p < 0.05). None of the single sperm traits/tests in vitro correlated significantly with in vivo fertility. A correlation with bull fertility was, however, found when measures of sperm traits were combined and predicted NRRs, calculated by regression analyses, were tested against observed 56d-NRRs. The predictive bull fertility, based on the tested three frozen batches, varied from 61.8 to 67.5% (p < 0.05) and was highly correlated with the observed fertility NRRs (r = 0.92, p < 0.001). Although the results suggest that the combined analyses of swim-up separated sperm traits, ZBA and IVF can be used to predict bull fertility, it might not be possible to determine the life-time fertility of a breeding sire owing to the limited number of observations made.

Animals↗
PubMed2001

Prediction of unexpectedly poor fertilization and pregnancy outcome using the strict criteria for sperm morphology before and after sperm separation in IVF-ET.

This study was performed to investigate if unexpectedly poor fertilization and in-vitro fertilization (IVF) outcome could be predicted using sperm morphology as diagnosed by the strict criteria. Sperm morphology was assessed in 137 IVF-ET cycles with at least three oocytes collected. The lowest amount of normal forms was 5% in 137 samples, indicating there were no patients belonging to 'poor prognosis' (<5% normal forms). Treatment using intracytoplasmic sperm injection (ICSI) was also excluded. Before sperm separation by the swim-up method, sperm morphology demonstrated a significant correlation with the fertilization rate (p < 0.0001). The fertilization rate (80.5%) in 110 'normal' samples (>14% normal forms) was significantly higher (p < 0.01) than that (55.4%) in 27 samples with 'good prognosis' (those with 5--14% normal forms). No embryo was available for transfer (ET) in 4 (3.6%) of 110 'normal' cycles and in 3 (11.1%) of 27 'good prognosis' cycles (not significant). Fresh ET was intentionally cancelled to avoid severe ovarian hyperstimulation syndrome (OHSS) in six of 110 'normal' cycles as well as in one of 27 'good prognosis' cycles. The pregnancy rate per ET was 31.0% (31/100) in the former group, while it was 26.1% (6/23) in the latter group. There was no difference between the two groups. In the post swim-up evaluation of sperm characteristics, morphology was significantly correlated with the fertilization rate in IVF-ET (p < 0.05) while other sperm parameters were not. When the cut off level for the post swim-up sperm morphology was set at 25%, there was a significant difference in the fertilization rates between patients (78.6%) with post-swim-up >25% and those (55.0%) with post-swim-up < or =25% (p < 0.01). Taken together, a relative indication for ICSI using sperm morphology before and after swim-up was established. Category A includes < or =14% normal forms in the ejaculate and post-swim-up < or =25%, while Category B includes < or =14% in the ejaculate and post-swim-up >25%. There was a significant difference in the fertilization rates between patients (47.2%) in Category A and those (60.2%) in Category B (p < 0.05). The clinical pregnancy rate was 11.1% for patients in Category A compared with 35.7% for patients in Category B. However, there was no significant difference between the two categories. These results indicate that the strict criteria provide a reliable estimation of the fertilizing ability of human spermatozoa. ICSI might be considered in Category A patients to avoid poor fertilization and pregnancy outcome.

Cell Separation↗
PubMed1984

[Polyploidy occurring during in-vitro fertilization of human oocytes: frequency and possible causes].

In an IVF-program a total of 585 oocytes (180 patients) was examined for the presence of pronuclei 16 to 20 hours after the addition of spermatozoa. The fertilization rate was 71% and in 58 (10%) of the fertilized oocytes three or more pronuclei, indicating a failure of the block to polyspermy with polyspermic fertilization, could be observed. The frequency of polyspermy was related to the maturity of the oocyte, determined according to morphological criteria. Immature oocytes showed a higher percentage of polyspermic fertilization (32%) compared to mature oocytes (6%). Preincubation of oocytes (0-1.5, 2-4, 5-8 hours) prior to the addition of spermatozoa increased the fertilization rate (67%, 70%, 83%, respectively). The polyspermy rate seemed to increase (13%, 14%, 19%). The observed frequency, however, was not significantly different between the various preincubation intervals. The polyspermy rate was affected by the number of spermatozoa used for in-vitro fertilization. Insemination with 0.5-0.8, 1.0 or 1.5 X 10(6) spermatozoa/oocyte resulted in a polyspermy rate of 6%, 20%, 32%, respectively. The appearance of polyspermic fertilization was not related to the age of the patient (20 to 45 years) nor to the method of ovarian stimulation (Clomiphene, hMG, Clomiphene/hMG). Because of the high incidence of polyspermy under in-vitro conditions it seems to be important to examine the oocytes in the pronuclear stage on a routine basis. Reduction of the number of spermatozoa used for in-vitro fertilization and the exact timing of insemination according to the maturity of the oocyte might reduce the occurrence of polyspermic fertilization.

Adult↗
PubMedDate not supplied

Impaired mouse fertilization by low chronic alcohol treatment.

Little is known about the effects of low chronic alcohol intake on fertility, particularly in females. Recently, we have shown that chronic 10% (w/v) ethanol treatment affects in-vitro fertilization of mouse female gamete. The aim of this study was to solve questions concerning the lowest dose and duration of ethanol treatment required to alter the fertility of immature and adult female and adult male mouse. Mice were treated with 5% and 2.5% (w/v) ethanol in drinking water for 4 weeks. The in-vitro fertilization rates were significantly decreased with the 5% ethanol when oocytes from prepubertal and pubertal ethanol-treated females were inseminated with spermatozoa from adult control males. The in-vitro fertilization rates were not diminished when oocytes from control females were inseminated with spermatozoa from adult ethanol-treated males. Haploid oocytes were increased when oocytes came from immature females treated with ethanol. The in-vitro fertilization rates were not decreased in adult treated females. The in-vivo fertilization rates were not modified when prepubertal ethanol-treated females were mated with adult control males. Fragmented oocytes, in the in-vitro fertilization experiments, were significantly increased when they came from prepubertal and adult treated females inseminated with ethanol-treated males. These results show that there is a threshold of the ethanol dose to produce an effect. Chronic low ethanol ingestion by immature female mice has a deleterious effect on their in-vitro fertilization. Furthermore, acute ethanol ingestion by adult females during the induction of ovulation resulted in high parthenogenetic activation and fragmentation of mouse oocytes.

Alcohol Drinking↗
PubMed1992

Usefulness of partial dissection of the zona pellucida in a human in-vitro fertilization programme.

The influence of partial zona dissection (PZD) on the fertilization rate was studied in 34 couples with a history of fertilization failure and/or severe sperm deficiency. Overall, PZD improved the rate of monospermic fertilization compared to controls (41/254 versus 6/111: P less than 0.001) and fertilization was achieved in 50% of cases. However, the results differed according to the seminal characteristics. In 10 couples with at least two in-vitro fertilization (IVF) trials entailing total fertilization failure and with semen defined as normal, PZD did not significantly improve the monospermic fertilization rate (6/44 in the PZD group versus 2/39 among controls). A benefit related to PZD was evident in 33 attempts with severe sperm deficiency. In this group, only four of 72 unmanipulated control oocytes were fertilized but the monospermic fertilization rate was 14.6% for PZD oocytes. The rates of polyspermy were 40% and 14.6% in the groups with normal and abnormal semen parameters respectively. Of 33 trials with defective spermatozoa, 20 reached the stage of embryo transfer and three pregnancies were obtained, of which one aborted at 9 weeks.

Female↗
PubMed1985

Fertility differences among male rabbits determined by heterospermic insemination of fluorochrome-labeled spermatozoa.

Spermatozoa from different bucks were stained with different fluorochromes, mixed, and inseminated heterospermically. By altering the interval between insemination and luteinizing hormone injection, spermatozoa were allowed to reside in the female tract approximately 5, 10, or 15 h prior to ovulation. The number of functional spermatozoa, from each male of a pair used, that was transported to the site of fertilization was estimated by counting total number of differently stained spermatozoa that surrounded or fertilized each oocyte. Spermatozoa from split ejaculates within a male competed against each other equally, indicating that the staining procedure did not affect fertilization or functional spermatozoal transport rates. Three pairs of males with high initial semen quality (greater than 80% motility) differed in fertility primarily due to functional spermatozoal transport. Spermatozoal survival in the female tract and capacitation time played a role in differences in male fertility when heterospermic insemination occurred at variable times relative to ovulation. Differences in fertilization not accounted for by spermatozoal transport ratio raised the possibility that rate of egg penetration due to acrosomal enzyme differences may be important in determining male fertility. Therefore, total acrosin, hyaluronidase, and arylsulfatase activity in spermatozoa from specific bucks used in fertilization experiments were determined. Although there were trends favoring high fertility when enzyme content was higher, the difference was significant only for arylsulfatase in one buck.

Animals↗
PubMed2002

Inhibition of in vivo and in vitro fertilization in rodents by gonadotropin-releasing hormone antagonists.

We have examined the effect of two GnRH antagonists, Ac-D-Nal(1)-Cl-D-Phe(2)-3-Pyr-D-Ala(3)-Arg(5)-D-Glu(AA)(6)-GnRH (Nal-Glu) and Ac(3,4)-dehydro-Pro(1),-p-fluoro-D-Phe(2),D-Trp(3,6)-GnRH (4pF), on in vivo and in vitro fertilization in rodents. Female rats were treated in the afternoon of proestrus with 2 micro l of Nal-Glu or 4pF (0.5 and 5 mM) injected directly into one oviductal horn (experimental); saline was injected into the contralateral horn (control). Females were then mated and the oviducts were perfused for egg and sperm recovery. The results indicate that both antagonists inhibited in vivo fertilization. Thus, the percentage of fertilized eggs in control oviducts ranged from 92% +/- 5% to 100% +/- 0%, whereas in treated oviducts, fertilization ranged from 25% +/- 6% to 73% +/- 5%. GnRH antagonists did not interfere with the process of ovulation, sperm migration to the site of fertilization, or early embryo development. In additional experiments with mice, GnRH antagonists inhibited in vitro fertilization. One fertilization event that was specifically inhibited by GnRH antagonists was the process of sperm binding to the zona pellucida. This step was precisely monitored using the hemizona assay. GnRH antagonists did not affect sperm movement or acrosomal status. These observations indicated that local treatment with GnRH antagonists inhibit in vivo fertilization and give additional support to the idea that endogenous GnRH may play an important role during fertilization by increasing the efficiency of sperm-zona binding.

Acrosome↗
PubMed2004

Use of Mammalian eggs for assessment of human sperm function: molecular and cellular analyses of fertilization by intracytoplasmic sperm injection.

PROBLEMS: Intracytoplasmic sperm injection (ICSI ) has been described as the 'cure' for male sterility because a single sperm can now be directly introduced into an egg with some chance of pregnancy. While ICSI has revolutionized the practice of assisted reproductive techniques (ART), there are few molecular and cellular studies about its safety and efficacy. Even by using ICSI, fertilization in humans succeeds only if the sperm effectively accomplishes a number of tasks including 'post-ICSI events' in fertilization. To assess the function of human sperm after ICSI, we used heterologous ICSI with human sperm into animal eggs. Egg activation, sperm decondensation and sperm centorosomal function were examined in sperm from fertile men and infertile patients. METHODS: Sperm from fertile men and infertile patients were injected into hamster, rabbit and bovine eggs by Piezo micromanipulator, and studied in decondensation of sperm nuclei, egg activation and microtubule organization. RESULTS: Decondensation human sperm head following ICSI into hamster eggs occurred initially form basal lesion, and apical portion of sperm nuclei which is surrounded by acrosome and perinuclear theca, still condensed in early pronuclear stage. Radial array of microtubules from sperm centrosome 'sperm aster' which is essential for pronuclear movement was observed in 30% rabbit eggs following ICSI with human sperm. By heterologous ICSI system with fertile human sperm and bovine eggs, 83.3% of eggs was activated and 60% eggs had sperm aster, indicating that bovine Piezo ICSI system is appropriate for assessing human sperm oocyte activation ability and human sperm centrosomal function. Oocyte activation and sperm centrosomal function were significantly low in sperm from men with globozoospermia and men with dysplasia of fibrous sheath. CONCLUSION: These assays indicate differences of the process of fertilization between in vitro fertilization and ICSI, and reflect the human sperm function especially for the 'post-ICSI events' in fertilization. More molecular and cellular analyses in fertilization by ICSI are needed for improvement of ART.

Acrosome↗
PubMed1984

Addition of an androgen-free epididymal protein extract increases the ability of immature hamster spermatozoa to fertilize in vivo and in vitro.

The fertility of spermatozoa from the different epididymal segments of hamsters was tested by in-vivo insemination. Caput and proximal corpus spermatozoa were non-fertile; spermatozoa from the distal corpus epididymidis fertilized 13% (38/290) oocytes and those from the proximal and distal cauda epididymidis 71 and 87%, respectively. When tested by in-vitro insemination, distal corpus spermatozoa penetrated 44% of oocytes while those from the distal cauda fertilized 87% of oocytes. Spermatozoa from the distal corpus recovered in Medium BMOC fertilized 13% (28/219) of oocytes in vivo, while those mixed with an epididymal protein preparation (0.8 mg protein/ml) fertilized 24% (49/204; P less than 0.01) of oocytes. When distal corpus spermatozoa were inseminated in vivo with 0.8 mg epididymal protein preparation 34% (31/90) oocytes were fertilized and only 22% (23/103; P less than 0.05) oocytes were fertilized when the proteins were obtained from epididymides of animals castrated for 30 days. When distal corpus spermatozoa were preincubated for 5 h in medium without (control) or with protein preparation (0.8 or 1.6 mg protein/ml), a significant increase in in-vitro oocyte penetration was found (25 compared with 45%; P less than 0.05) when the protein was present at 1.6 mg/ml. These results confirm and extend previous observations suggesting a role for androgen-dependent glycoproteins secreted by the epididymis in the acquisition of fertilizing ability that occurs during sperm maturation.

Animals↗
PubMed1992

[Fertilizing ability in vitro of golden hamster spermatozoa after acute testicular X-irradiation].

The present study is concerned with the effect of radiation to the testis on fertilizing ability in vitro using golden hamster spermatozoa. Male hamsters at 6 and 8 weeks of age were given acute testicular X-irradiation (200 kVp, 20 mA, 0.47-0.48 Gy/min). Spermatozoa were collected from the cauda epididymides at different times after irradiation and then they were suspended in fertilization medium. After preincubation for 4-5 hr, the spermatozoa were cultured with the eggs collected from mature hamsters treated with PMSG-hCG. Fertilized eggs were examined for incidence of sperm penetration and formation of pronuclei at 4-5 hr after insemination. The fertilization rate (47.7%) at the 6th week after irradiation with a dose of 2 Gy was much lower in comparison with the control value (92.6%). However, the fertilization rates at the 3rd and 9th weeks after irradiation were 97.7 and 90.6%, respectively. In these period, no difference was found between the irradiated groups and the control groups. From the changes in sperm concentration after irradiation with a dose of 2 Gy, it was found that the fertilization rate was the lowest at the 6th week. The sensitive stage to radiation during spermatogenesis with reference to the reduction of fertilizing ability after irradiation coincides with that of decrease in the sperm concentration and sperm motility. The results of fertilization rate at the 6th week after different doses of X-irradiation (0.25-6 Gy) indicated that the reduction of fertilization rate is nearly expressed as a dose-response relationship.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Prediction of fertility from calfhood traits of Angus and Simmental heifers.

The objectives of this study were to quantify the relationships between traits observed before the first breeding season and fertility of 946 Angus and 351 Simmental heifers and to use those traits to develop prediction equations for heifer fertility. Logistic regression methodology was used. Traits investigated were Julian birth date, age of the heifer's dam, birth weight, actual weaning and yearling weights, weaning and yearling weight ratios, 205-d weight, 365-d weight, and birth-weaning, weaning-yearling, and birth-yearling ADG and relative growth rate (RGR). In both breeds heifers that were younger at the start of the breeding season were less likely to conceive, but this effect was more important for Angus (logistic regression coefficient, b = -.032; P less than .01) than for Simmentals (b = -.015; P = .06). Weaning weight ratio was positively associated with heifer fertility (b = .025; P = .01 and b = .028, P = .04, respectively, for Angus and Simmental), whereas actual weaning weight was related curvilinearly to fertility of Angus heifers. The likelihood of conception was highest for Angus heifers weighing greater than or equal to 240 kg at weaning. The only postweaning trait associated with heifer fertility was weaning-yearling RGR. The likelihood of conception was highest for Angus heifers growing between .15 and .30% per day (P = .01), whereas fertility increased continuously (P = .04) for Simmental heifers as weaning-yearling RGR decreased. The maximum variations in fertility explained by models including all possible explanatory variables were 11.5 and 9.2% for Angus and Simmental, respectively. Results suggested that growth-related traits were relatively more important as a predictor of fertility for Simmental heifers and that age at the start of the breeding season was more important for Angus heifers. The combination of Julian birth date and weaning-yearling RGR produced the best models to predict heifer fertility for both breeds.

Animals↗