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At least 19 recordsLinked to original sources
PubMed1992

A comparison of the frequency and type of chromosomal abnormalities in human sperm after different sperm capacitation conditions.

Human sperm karyotypes can be prepared after fusion of human sperm with Golden hamster oocytes. Most laboratories use one of two methods of sperm capacitation: incubation of freshly-ejaculated sperm in Biggers, Whitten, and Whittingham (BWW) medium for 5-7 h at 37 degrees C or sperm storage in (N-tris [hydroxymethyl]methyl-2-aminoethanesulfonic acid; 2-([2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino)ethanesulfonic acid) (TES)-Tris yolk buffer (TYB) for 1-3 days at 4 degrees C. Since there have been conflicting reports as to whether there is a difference in the frequency of structural chromosomal abnormalities between BWW capacitation and storage in TYB for 2 days, we analyzed a larger number of karyotypes (8974) from 136 donors to determine if there was any difference in the frequency or type of chromosomal abnormalities in sperm treated by fresh BWW capacitation, storage in TYB for 1 day (TYB-1), or storage in TYB for 2 days (TYB-2). There was no difference in the frequency of numerical chromosomal abnormalities or sex ratio in any of the three treatment groups. However, there was a significantly increased frequency of structural chromosomal abnormalities after storage in TYB-1 and TYB-2. There was no difference in the frequency or type of structural chromosomal abnormalities after sperm storage in TYB-1 compared to TYB-2.

Adult↗
PubMed1992

Purification and characterization of a human follicular fluid lipid transfer protein that stimulates human sperm capacitation.

Identification of the mechanisms responsible for sperm capacitation has been an active area of research for nearly four decades. Changes in the lipid composition of the sperm membrane is one of the biochemical events that occurs during sperm capacitation. We have been studying physiological effectors of some of these changes and have identified lipid transfer activity in fractions of human follicular fluid that stimulates sperm penetration of zona-free hamster oocytes. We report here the purification of a lipid transfer protein by sequential chromatography from human follicular fluid. This protein was purified greater than 20,000-fold for lipid transfer activity and greater than 28,000-fold for sperm penetration-inducing activity. This 64,000 molecular weight protein has a pI of approximately 5.0 and shares physicochemical characteristics with the plasma lipid transfer protein, LTP-I. Antibodies to LTP-I also recognize this protein and depletion of LTP-I from human follicular fluid by immunoaffinity chromatography renders the follicular fluid incapable of stimulating sperm penetration. We conclude that purified LTP-I is able to stimulate human sperm capacitation and that LTP-I is a molecule responsible for this stimulation in follicular fluid.

Antibodies, Monoclonal↗
PubMed1992

In vitro sperm capacitation to treat antisperm antibodies bound to the sperm surface.

Our objective was to study antisperm antibody bound to the acrosome region during in vitro capacitation and to determine whether acrosome-antibody free sperm can be obtained from previously acrosome-antibody-coated sperm. The spermatozoa from a selected series of 14 patients were tested for sperm antibodies bound to the sperm surface using d-IBT and focusing on the acrosome positivity. The tests were carried out before the incubation and after 3, 6, 9, and 12 h of incubation in Tyrode's solution with 0.5% human serum albumin as the capacitation medium. Tests to evaluate acrosome region, sperm motion parameters, and zonae binding ability were carried out. In this way we were able to evaluate sperm function during capacitation protocol. The patients were 14 subjects selected according to good seminal characteristics, good post-rise sperm parameters, and high percentage of ASA bound to the sperm surface. In all cases the results showed that antisperm antibodies bound to the acrosome region were shed prior to the acrosome reaction. During sperm capacitation in human a modification, migration, or shedding of plasma membrane molecules takes place. The presence of antibodies in such an important area of the sperm head could certainly interfere in the fertilization process. Our data indicate that in vitro capacitation could provide an in vitro therapy capable of eluting antibodies from the acrosome region.

Acrosome↗
PubMed1992

Effects of modulators of protein kinases and phosphatases on mouse sperm capacitation.

We examined effects of modulators of protein kinases and phosphatases on the kinetics of mouse sperm capacitation. The chlortetracycline fluorescence assay was used to monitor the process of capacitation (in terms of the appearance of the B pattern). The treatment of sperm with dibutyryl cyclic AMP (cAMP) or dibutyryl cGMP resulted in a higher percentage B pattern at various times during capacitation compared with the control. The addition of 100 microM H8 inhibited the cyclic nucleotide-dependent stimulation of capacitation. Tumor promotors, 12-O-tetradecanoyl phorbol 13-acetate (TPA; a stimulator of protein kinase C) and okadaic acid (an inhibitor of protein phosphatases 1 and 2A), induced a rapid appearance of the B pattern (15 min after addition) and maintained a percentage B pattern similar to that of the control in the later period of capacitation. An inhibitor of protein kinase C, staurosporine, inhibited the TPA-dependent acceleration of capacitation. Furthermore, the addition of genistein, an inhibitor of protein tyrosine kinases, resulted in a strong inhibition of capacitation. All agents tested did not affect sperm motility. These data suggest that protein phosphorylation and dephosphorylation may play regulatory roles in mediating mouse sperm capacitation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Sperm capacitation in the domestic cat (Felis catus) and leopard cat (Felis bengalensis) as studied with a salt-stored zona pellucida penetration assay.

The ability of domestic cat or leopard cat spermatozoa to penetrate zonae pellucidae (ZP) of salt-stored, domestic cat oocytes was examined as an assay for sperm capacitation. Ovarian oocytes were recovered after ovariectomy and matured in vitro for 18-36 h. Following removal of cumulus cells, the oocytes were used fresh, or stored (4 degrees C, 0.5-24 weeks) in a HEPES-buffered hypertonic salt solution. Electroejaculated, washed sperm (2-4 x 10(6) sperm/ml) were preincubated for 1.0 h (38 degrees C, 5% CO2 in air) and then co-incubated (2 x 10(5) sperm/ml) with fresh or stored oocytes for 6.0 h. Gametes were incubated in a protein-free, modified Tyrode's solution (TLP-PVA) or in the same medium containing 4.0 mg/ml bovine serum albumin (BSA; TALP-PVA). Treatments were compared for percentage ZP penetration (defined as sperm heads reaching more than halfway through the ZP) as an index of sperm capacitation. In both the domestic cat and leopard cat, there was no difference (P greater than 0.05) in sperm penetration of fresh ZP (domestic cat, 42.5 +/- 5.4%; leopard cat, 38.6 +/- 2.8%) or stored ZP (domestic cat, 32.4 +/- 4.2%; leopard cat, 27.6 +/- 2.3%). Sperm incubated in protein-free medium (TLP-PVA) were less capable (P less than 0.05) of ZP penetration (domestic cat, 14.6 +/- 5.9%; leopard cat, 7.9 +/- 3.0%) than sperm incubated in medium TALP-PVA containing BSA (domestic cat, 60.3 +/- 5.9%; leopard cat, 58.4 +/- 3.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Effect of various hexoses on sperm capacitation and penetration of rat eggs in vitro.

Fertilization of rat eggs in vitro could not be achieved when epididymal spermatozoa were preincubated and eggs in clots incubated in a chemically defined medium without D-glucose. Very high proportions (84-100%) of eggs examined were undergoing fertilization when 2.78-8.34 mM-D-glucose were included in the medium. The substitution of D-fructose or D-galactose for D-glucose resulted in very poor penetration rates (0-4%), but D-mannose was effective for fertilization (59-99% penetration). Incubations for sperm capacitation and egg fertilization in different media containing the various hexoses showed that rat epididymal spermatozoa could be partly capacitated without hexose, that D-glucose, D-mannose or D-galactose but not D-fructose is effective for sperm capacitation and that only D-glucose and D-mannose supported penetration of eggs in vitro.

Animals↗
PubMed1992

Evaluation of a TEST-yolk sperm capacitation system for use in bovine in vitro fertilization.

Bovine sperm acquire the ability to penetrate zona-free hamster oocytes (capacitation) after incubation in TEST-yolk buffer. Our objective was to determine whether such sperm could penetrate zona-intact bovine oocytes in vitro. Bovine cumulus enclosed oocytes from 2- to 5-mm follicles were incubated in maturation medium for 24 h at 37 degrees C. Ejaculated bovine semen was diluted 1: 10 in TEST-yolk buffer, cooled to 4 degrees C, and stored for 8 h to induce capacitation. Sperm were then washed thrice in pH 7.6, .15 M NaCl containing .1% bovine serum albumin V (37 degrees C) and diluted to 2 x 10(6) sperm/ml in fertilization medium. Droplets of fertilization medium containing capacitated sperm, killed sperm, or no sperm were made under paraffin oil. Oocytes (matured 24 h) were added and cocultured with sperm for 8 h and then transferred to fresh fertilization medium for 40 h. After 24 h, 53% of the oocytes had matured (metaphase II). The fertilization rate of the metaphase II oocytes (203) with TEST-yolk capacitated sperm was 87%, whereas the parthenogenetic controls were 2 and 0%, respectively. Therefore, TEST-yolk buffer can be used to capacitate bull sperm for in vitro fertilization.

Animals↗
PubMed1979

Is prolactin involved in sperm capacitation?

Immunoreactive prolactin in high concentration was detected in the human semen. Therefore, the effect of prolactin on the various metabolic parameters of the human spermatozoa was studied. It was found that prolactin brought about many of the biochemical changes in the spermatozoa which are known to be associated with the process of capacitation. These results suggest that prolactin has a role in the sperm capacitation.

Acrosome↗
PubMedDate not supplied

Albumin is required for the guinea pig sperm capacitation but is not essential for acrosome reaction and fusion with eggs.

The importance of serum albumin in supporting guinea pig sperm capacitation, acrosome reaction, and fusion with eggs in vitro was studied by incubating the spermatozoa in albumin-free medium containing different synthetic polymers. Serum albumin was found to be an obligatory component in the incubating medium for the capacitation of guinea pig spermatozoa. Albumin in the medium is not essential for the acrosome reaction and fusion with the eggs, but these phenomena take place most efficiently in presence of albumin.

Acrosome↗
PubMed1992

Requirements for successful mammalian sperm capacitation and fertilization.

The function of sperm is to fertilize oocytes, thereby providing necessary genetic information and triggering oocyte activation and subsequent metabolic activities that are vitally necessary for successful mammalian embryonic development. Although motile when they leave the male reproductive tract, mammalian sperm are nonfertilizing; they require a further period to complete the maturation initiated in the epididymis. This final maturation phase is called capacitation and is absolutely crucial for successful sperm:oocyte interaction. Capacitation, which exhibits a species-dependent time requirement, involves loss of proteins from the sperm surface; additionally, it has been shown to be dependent on the composition of the environment. Adequate free calcium (Ca2+), sodium (Na+), and potassium (K+), and energy substrates play roles in regulating capacitation, hyperactivated motility, the acrosome reaction, and fusion with the oocyte plasma membrane. In general, conditions present within the female reproductive tract are permissive, ie, appropriate levels of the constituents are present. Therefore, the failure to achieve conception in some couples suggests that there may well be basic physiological defects in the sperm of the male partner. Current research in many laboratories is directed toward identifying such individuals and, in time, developing appropriate therapeutic treatments.

Animals↗
PubMed1992

The fertilization antigen-1 does not have proteolytic/acrosin activity, but its monoclonal antibody inhibits sperm capacitation and acrosome reaction.

OBJECTIVE: To determine if human sperm surface fertilization antigen exhibits proteolytic or acrosin activity and to investigate the mechanism(s) whereby monoclonal antibody (mAb) to fertilization antigen inhibits human sperm penetration of zona-free hamster ova. DESIGN: Proteolytic and acrosin activities of human fertilization antigen were determined. Acrosomal status, acrosin activity, and motion characteristics were evaluated after incubation of human sperm with immunoaffinity-purified mAb to fertilization antigen. SETTING: Academic research environment. PARTICIPANTS: Fertile donors used as controls for infertile patients for fertility evaluation. INTERVENTIONS: Human spermatozoa were treated with mAb to fertilization antigen and induced to undergo acrosome reaction using calcium ionophore A23187. MAIN OUTCOME MEASURES: Proteolytic and acrosin activities of fertilization antigen. Sperm penetration assay, acrosomal status, and motion parameters. RESULTS: Fertilization antigen does not exhibit proteolytic or acrosin activity; however, its mAb completely blocks human sperm penetration of zona-free hamster ova. The mAb to fertilization antigen inhibits ionophore-induced acrosome reaction and blocks development of the hyperactivated state of human sperm cells. CONCLUSIONS: Monoclonal antibody to fertilization antigen blocks fertilization by inhibiting capacitation and acrosome reaction.

Acrosin↗
PubMedDate not supplied

Effect of spermine on sperm capacitation of guinea pig in vitro.

Spermine (Sp) 10(-5) mM had vigorous activity of guinea pig spermatozoa, while it completely abolished sperm forward motility (SFM) at a concentration of 10(-3) mM. There appeared to be a dose relationship to inhibition to motility. 2-Difluoromethylornithine 10 mM antagonized the Sp-induced inhibition of SFM after 3 h of incubation. Capacitation of a guinea pig sperm was inhibited by Sp in a concentration-dependent manner. The majority of acrosome-reacted sperm did not display hyperactivated motility. Precapacitated sperm were able to undergo the acrosome reaction (AR) in the presence of Sp. Moreover, Sp-mediated inhibition of capacitation was a reversible process. Once sperm capacitation was completed, Sp no longer inhibited AR. Before capacitation, the content of Sp in spermatozoa was 4.5 +/- 0.5 micrograms/5 x 10(7) cells, whereas in case of capacitated spermatozoa it was significantly decreased (2.1 +/- 0.4 micrograms/5 x 10(7) cells). The penetration of spermatozoa into the zona-free hamster eggs in the presence of Sp was markedly decreased, but it did not affect the fertilizability of ova as compared to the control. These results suggest that Sp may be an inhibitory agent of sperm capacitation in guinea pig in vitro, and it may also be involved in the modulation of capacitation.

Acrosome↗