Biomedical subjects

Xing-yu Wu

Publications and source records attributed to Xing-yu Wu.

16 recordsLinked to original sources

PubMed2005

Changes of hippocampus somatostatin and learning ability in rats after +Gz exposure.

OBJECTIVE: To investigate changes of learning ability and somatostatin (SS) changes after positive acceleration (+Gz) exposures. METHOD: Eighty male SD rats were randomly divided into 3 groups: control group (Con), +6 Gz/3 min group (+6 Gz), and +10 Gz/3 min group (+10 Gz), 8 rats in each group. Changes of learning ability in rats were observed at 0 d, 2 d, 4 d and 6 d after +Gz exposure. SS in hippocampus was measured by RIA at 0 d, 2 d and 4 d after +Gz exposures (there were 8 rats every time, in each group). RESULT: In Y-maze test, number of correct response decreased significantly (P<0.01), and total reaction time increased significantly (P<0.01) in +6 Gz and +10 Gz groups as compared with control group; number of correct response and total reaction time in +10 Gz group changed significantly at 0 d (P<0.01 or P<0.05) as compared with +6 Gz group. RIA showed that, content of SS in hippocampus declined at 0 d and 2 d (P<0.05 or P<0.01) in +6 Gz and +10 Gz groups as compared with control group. CONCLUSION: +Gz exposure could impair learning ability of rats, and inhibit expression of SS in hippocampus.

Acceleration↗

PubMed2005

[Effects of simulated weightlessness on ALP, ACP, collagen I, and biomechanics of hind-limb bones in rats].

OBJECTIVE: To investigate effects of 3 weeks simulated weightlessness on biomechanical parameters, alkaline phosphatase (ALP), acid phosphatase (ACP) and collagen I of hind-limb bones in tail-suspended rats. METHOD: Fourteen male SD rats were divided equally into control group (CON) and experimental group; tail-suspended (TS) was used to simulate weightlessness. After 3 weeks tail-suspension, biomechanical parameters of femur were measured; ALP, ACP and collagen I of tibia were observed. RESULT: Elastic load, maximum load, and bending rigidity coefficient decreased significantly (P<0.01), while the maximum deformation and bending toughness coefficient increased markedly (P<0.01 or P<0.05). Morphological results showed that ALP declines significantly in TS group, ACP and type I collagen increased significantly in TS group. CONCLUSION: After tail-suspension for 3 weeks, growth of rat's weight bearing bones are suppressed, biomechanical capability declines, and collagen I metabolism becomes disordered.

Acid Phosphatase↗

PubMed2004

[Effects of combined stress of high +Gz and noise on learning and memory in rats].

OBJECTIVE: To study the effect of combined stress of noise and + Gz on learning and memory in rats. METHOD: Thirty-two male SD rats were randomly divided into 4 groups: control group, +10 Gz/3 min group, 90 dB(A)/30 min noise group, combined stress group (+10 Gz/3 min and 90 dB(A)/30 min), 8 rats in each group. Changes of learning and memory after stresses were measured by means of Y-maze test, open field test and step-through test. RESULT: As compared with control group and noise group, the number of correct reactions decreased significantly (P<0.01) and the reaction time increased significantly (P<0.01) in combined stress group at all time after stress; time stay in center grille (TSCG) increased significantly immediately after stress (P<0.01). When compared with control group, total time (TT) and number of error (NE) increased significantly (P<0.01) while latent time (LT) decreased significantly immediately and 6 d after stress (P<0.01). As compared with +10 Gz group, number of correct reactions in combined stress group decreased significantly (P<0.05) and reaction time increased significantly (P<0.01) immediately after stress. CONCLUSION: It is suggested that combined stress of noise and +Gz may impair learning and memory of rats, and +Gz seems to contribute more to the combined effects.

Acceleration↗

PubMed2004

[Effects of BMP-2 on the gene expression of rat osteosarcoma cells under simulated weightlessness].

OBJECTIVE: To investigate the effect of BMP-2 on (the) gene expression of rat osteosarcoma cells (ROS17/2.8) under rotating clinostat simulated weightlessness. METHOD: ROS17/2.8 cells were cultivated in 1 G control and rotating clinostat simulated weightlessness with 500 ng/ml BMP-2 in the culture medium. Total RNA in cells was isolated after 24, 48 and 72 h. Reverse transcription PCR analysis was made to examine the gene expression of alpha 1 chain of type I collagen (collagen I alpha 1) and alkaline phosphatase (ALP). RESULT: The expression of COL-I alpha 1 mRNA induced by BMP-2 was much more than that without BMP-2 in 24 h and 48 h group (P<0.01). The level of ALP mRNA induced by BMP-2 was significantly high in 48 h or 72 h group (respectively P<0.01, P<0.05). The level of BMP-2 induced expression of COL-I alpha 1 mRNA was significantly lower under 48 h of simulated weightlessness than in 1 G condition (P<0.01). The level of ALP mRNA was significantly lower under simulated weightlessness for 48 h or 72 h (P<0.01). CONCLUSION: BMP-2 can stimulate the differentiation of ROS17/2.8 cells in 1 G condition and this process is reduced under simulated weightlessness.

Alkaline Phosphatase↗

PubMed2003

[Effects of rotating clinostat simulated weightlessness on the differentiation-related gene expression of ROS17/2.8 cells].

OBJECTIVE: To investigate the effects of rotating clinostat simulated weightlessness on the differentiation-related gene expression of ROS17/2.8 (rat osteosarcoma) cells. METHOD: Cultured ROS17/2.8 cells were exposed to rotating clinostat simulated weightlessness for 24, 48 and 72 h with control group in 1 G condition. Total RNA in cells was isolated and reverse transcription PCR analysis was made. Gene expression of type I collagen alpha 1 chain and alkaline phosphatase were examined by their ratios to beta-actin. RESULT: The expression of type I collagen alpha I chain and alkaline phosphatase (ALP) gene was significantly lower after 72 h exposure to clinostat simulated weightlessness than that of the control group (P<0.01). CONCLUSION: Differentiation of rat osteosarcoma cells was reduced after exposure to rotating clinostat simulated weightlessness for 72 h.

Alkaline Phosphatase↗

PubMed2003

[Weightlessness or weightlessness simulation and vascular remodeling].

Weightlessness is inavoidable during spaceflight. It brings profound physiological effects on human body. Vascular remodeling is one of the important changes of cardiovascular system caused by weightlessness or simulated weightlessness. The paper summarized the studies on the effects of weightlessness or weightlessness simulation on vascular remodeling in recent years. The emergence and development of the concept of vascular remodeling were briefly reviewed. The advances of study on vascular remodeling in recent years was briefly discussed with the points focused on the effects of weightlessness or weightlessness simulation on cardiovascular remodeling and its mechanism. It is proposed that cardiovascular remodeling might be important in studying the causes of orthostatic intolerance after spaceflight.

Adaptation, Physiological↗

PubMed2003

[Effects of microgravity on the gene expression and cellular functions of osteoblasts].

Skeleton system may adapt to multiform mechanical stimulus including gravity so as to modulate the balance between bone formation and absorption. Osteopenia under microgravity is mainly due to decrease of bone formation which relates closely to the low level of osteoblast activity. The proliferation and adhesive ability of osteoblast are reduced. The cells also express less messenger and protein of the differentiation and maturation-related substances, such as alkaline phosphatase, osteocalcin and type I collagen. The secretion of many growth factors is decreased and osteoblast responses less to them. It still remains unknown why the osteoblast is disfunctioned under microgravity. A hypothesis suggests the cellular shape changes may be the answer.

Alkaline Phosphatase↗

PubMed2003

[Changes of dentin, dental pulp and periodontium tissue in tail-suspended rats].

OBJECTIVE: To investigate the metabolic changes of calcium and phosphorus in dentin, dental pulp and periodontium in tail-suspended rats, and the functions of TGF-beta 1, c-fos, collagen-I and collagen IV in dentin, dental pulp and periodontium. METHOD: Relative percentage contents of Ca, P in dentin, dental pulp and periodontium were measured with scanning electron microscope and energy spectrum analytical system in 3 groups of rats. The expression of TGF-beta 1, c-fos, collagen-I and collagen IV were also observed. RESULT: In the suspension group, the relative percentage content of Ca declined significantly, while P increased slightly. There were no significant differences of Ca, P in alveolar bone. The expressions of TGF-beta 1, c-fos and collagen-I declined, but the expression of collagen-IV in pulp vessel increased. There were no significant changes of expressions of TGF-beta 1, c-fos, collagen-I and collagen-IV in the vicinity of PDL. After adopting artificial countermeasures, the above expressions restored partly. CONCLUSION: Weightlessness might cause abnormal mineralization in dentin, and 1.5 G artificial countermeasures could eliminate the above changes of mineral metabolism. The poor mineralization of dentin might be associated with the reduced secretion of TGF-beta 1, c-fos and collagen-I in tail-suspended rats.

Animals↗

PubMed2003

[Changes of bone morphogenesis proteins and transforming growth factor-beta in hind-limb bones of 21 d tail-suspended rats].

OBJECTIVE: To investigate changes of bone morphogenesis proteins (BMP), transforming growth [correction of grouth] factors-beta (TGF-beta) in tibia and the growing of femur in tail-suspended rats after 21 d simulated weightlessness. METHOD: Fourteen male SD rats were randomly divided into control group (CON) and tall-suspension group (TS). After 21 d tail-suspension, basic physical parameters of the femur were measured; changes of BMP, TGF-beta in tibia were assayed by immunohistochemical method. RESULT: During 21 d tail-suspension, all rats grew well without apparent stress reaction. After 21 d weightlessness simulation, wet weight, dried weight, ash, diameter and density of femur in TS group declined significantly (P<0.01). Immunohistochemical results of tibia showed that both BMP and TGF-beta declined in tissues from all regions of the tibia. CONCLUSION: After 21 d tall-suspension, the growth of rat's weight bearing bones were suppressed, production and secretion of BMP and TGF-beta was holdback.

Animals↗

PubMed2002

[Effects of repeated +Gz exposures on the expression of c-fos protein in rabbit brain].

OBJECTIVE: To investigate the effect of repeated +Gz exposures on the expression and distribution of c-fos protein immunoreactivity in rabbit brain. METHOD: Twenty rabbits were divided randomly into 4 groups (n=5 in each group). Animals were anesthetized and then exposed to +4 Gz until 30 s after the arterial pressure at eye level dropped to 0 kPa. The exposure was repeated for 3 times with 30 min intervals. The expression of c-fos protein in rabbit brain was examined at 0 h, 1 h and 6 h after +Gz exposure by immunohistochemistry method. RESULT: c-fos protein was obviously expressed in cortex, the third ventricle, hippocampus and dentate gyrus immediately after repeated +Gz exposures, and strongly expressed 1 h after the exposure, and then had a tendency to decrease 6 h after the exposure. CONCLUSION: Three +Gz exposures may cause time-dependent c-fos expression in rabbit brain, which may be involved in +Gz-induced brain damage.

Aerospace Medicine↗

PubMed2002

[Effects of simulated weightlessness on the expression of cyclooxygenase-2 in rat calvarial osteoblasts induced by fluid shear stress].

OBJECTIVE: To investigate the effect of simulated weightlessness on mechanotransduction in rat calvarial osteoblasts. METHOD: Osteoblasts were isolated from neonatal rat calvariae and then were set to two groups. One was cultured in clinostat to simulate the weightlessness environment. Another was cultured in 1 G gravitational environment. After 60 h, osteoblasts were treated with 0.5 Pa or 1.5 Pa FSS in a flow chamber. The FSS treatment time was set to 30 min and 60 min, respectively. The specimens of each group were obtained for immunohistochemistry staining and determination of expressions of cyclooxygenase-2 (COX-2) in osteoblasts. RESULT: In osteoblasts cultured in 1 G gravitational environment, COX-2 expression was increased remarkably from 30 min to 60 min with the treatment of FSS (P<0.01). There was no clear difference between the expression of COX-2 after treatments of 0.5 Pa or 1.5 Pa FSS; In cells cultured in simulated weightlessness environment, no detectable expression of COX-2 was found with the treatment of 0.5 Pa FSS. The expression of COX-2 was only detected after 60 min treatment of 1.5 Pa FSS, but the level of expression was decreased significantly (P<0.01). CONCLUSION: These results demonstrated that the mechanotransduction in osteoblasts was down-regulated in simulated (correction of stimulated) weightlessness.

Animals↗

PubMed2002

[Upright tilt table testing and syncope evaluation].

Syncope is a state of unconsciousness, the process of syncope is sudden and transient. Transient and widespread cerebral ischemia/hypoxia are the reasons of syncope. Sixty percent to seventy percent of the patients suffering from syncope have no categorical reasoning, although lots of assisted examinations had been carried out. Those syncope are called unexplained syncope or unknown origin syncope. Basic upright tilt table test, as well as isoproterenol tilt table test, is a quite effective diagnostic technique for unexplained syncope. This paper reviewed the value of upright tilt [correction of tile] table test in diagnosing unexplained syncope. The method of experiment, information of it's clinical application and points for attention with test were also introduced.

Brain Ischemia↗

PubMed2002

[Changes of serum alkaline phosphatase and electrolytes during 21 d head down bed-rest].

Objective. To investigate the effect of simulated weightlessness on serum alkaline phosphatase (ALP), calcium, magnesium, chlorine and phosphorus. Method. 6 healthy males, aged 24.8 +/- 6.1, were exposed to -6 degrees HDT bed rest for 21 d. Activity of serum alkaline phosphatase, serum contents of calcium (Ca), magnesium (Mg), chlorine (Cl) and phosphorus (P) ions were assayed before HDT (d-3), on the 3rd, 10th and 21st day during HDT and after HDT (d+2). Ca was measured by methyl thymol blue method, P was determined with ultraviolet spectrophotography, determination of Mg and Cl were made with enzyme method, ALP was examined with 4-nitrobenzene phosphate method. Result. Serum Ca2+ levels were significantly higher at d10, d2l and d+2 than the value of d-3 (P<0.01). P3+ levels declined significantly on d2l as compared with d-3 (P<0.01). During the HDT and after HDT, Mg2+ declined to a level below that before HDT (P<0.05 or P<0.01). Cl- were significantly higher at d2l and d+2 than the value of d-3 (P<0.01). ALP level was higher on d2l than on d-3 (P<0.01). Conclusion. 21 d HDT induced increase of Ca, Cl, ALP, and decline of Mg and P. The changes may reflect the imbalance of metabolism.

Adult↗

PubMed2002

[Effects of simulated microgravity on cardiovascular function and counter effect of lower body negative pressure].

Studies on effect of simulated microgravity on cardiovascular function and counter effect of lower body negative pressure (LBNP) in recent years were summarized. The mechanism of simulated microgravity induced orthostatic intolerance may involve the reduction of cardiovascular function and cerebral blood flow, and endocrine changes. The significance of mathematical model in the study of mechanism of microgravity induced orthostatic intolerance was also discussed. The counter effect of LBNP was emphasized.

Bed Rest↗

PubMed2002

[Influences of repeated lower +Gz exposures on high +Gz exposure induced brain injury in rats].

Objective. To explore the influence of repeated lower +Gz exposures on high +Gz exposure induced brain injury in rats. Method. Forty SD male rats were randomly divided into control group (5 rats), +10 Gz/5 min group (5 rats) +4 Gz exposure one time, three times and five times group (10 rats each group). After 1 d or 6 d of +4 Gz exposure each group were exposed to +10 Gz again. Three days after +10 Gz exposure the neuron damage was observed by light microscope in HE stained section. Result. There was no brain damage after repeated +4 Gz/3 min exposure 5 times so it was reasonable to use this exposure intensity as ischemia stimulation. +10 Gz/5 min exposure could result in irreversible neuron damage such as neuron degeneration and coagulation necrosis. The experiment results suggested that after +10 Gz/5 min exposure there were degenerated neurons in cortex, hippocampus and thalamus. The number of degenerated neurons were obviously decreased in cortex, hippocampus and thalamus when exposed to +10 Gz/5 min again after repeated +4 Gz/3 min 3-5 times. Conclusion. The degree of neuron damage was obviously slight at the time of exposure to +10 Gz/5 min again after repeated +4 Gz/3 min 3-5 times. The ischemia tolerance at the time of exposure to +Gz was similar to other brain ischemia.

Animals↗

PubMed2002

[Effects of simulated weightlessness on pressure-volume relationships of femoral vein of New Zealand Rabbits].

Objective. To observe the changes of pressure-volume relationships of rabbit femoral veins and their structural changes caused by simulated weightlessness. Method. Head-Down Tilt (HDT) -20 degrees rabbit model was used to simulate weightlessness. Twenty four healthy male New Zealand Rabbits were randomly divided into 21 d HDT group,10 d HDT group and control group, (8 in each group). Pressure-volume (P-V) relationship of rabbits femoral veins was measured and the microstructure of the veins was observed. Result. The femoral vein P-V relationship curves of HDT groups showed a larger volume change ratio than that of control group. This change was that 21 d HDT group was even more obvious than that of HDT-10 d group. B1 and B2 in quadratic equations of 21 d HDT group were significantly higher than the values of both 10 d HDT group and control group during expansion (inflow) and collapse (outflow) (P<0.01). The result of histological examination showed that the contents and structure of femoral vein wall of HDT-rabbits changed significantly. Endothelial cells of femoral vein became short and columnar or cubic, some of which fell off. Smooth muscle layer became thinner. Conclusion. Femoral venous compliance increased after weightlessness-simulation and the femoral venous compliance in 21 d-HDT rabbits increased more obviously than that in 10 d-HDT rabbits. The structure of femoral vein wall had changed obviously.

Adaptation, Physiological↗