| Objective: To study the dynamic change of hypothalamic-pituitary-adrenal axis and hypothalamic-pituitary-thyroid axis on different altitude gradient hypoxic environment,explore the influence of hypoxia inducible factor-1 and vascular endothelial growth factor expression on hypoxic environment and the relevance of high altitude pulmonary edema and the high altitude cerebral adema, observe the dynamic changes of sex hormone and the number of red blood cells in rats on hypoxic environment.Methods :Rats were randomly divided into four groups, 1500m(control), 3500 m, 5000 m and 6000 m. Then, each group were divided into hypoxia 12 h subgroup, 24 h subgroup, 48 h subgroup. There were totally 12 groups with 8 rats in each group. The control group were put in department at an altitude of 1500 m, the hypoxia groups were put at different altitude in hypobaric chamber. After collecting blood and separating lung and brain tissue, the water contents in rats lung and brain were determined by dry-wet proportion method, and histopathologic changes were observed with HE staining. Then, separating testis and epididymis tissue,weigh and calculate testis and epididymis indexs. The contents of CRH?ACTH?GC?TRH?TSH?T3?T4?T?E2?VEGF in serum were determined with ELISA. Real time PCR to detect expression of HIF-1?m RNA?VEGF m RNA. Blood cell analyzer to determine the number of red blood cells(RBC), hemoglobin(HGB) content.Results: The three main indicators hormone of HPA axis(CRH,ACTH,GC) were increased with the increasing of altitude, compared with 1500 m at the same time there were statistically significances(P<0.05 or P<0.01), compared with 0h at the same elevation there were statistical significances(P<0.05 or P<0.01). They were increased rapidly with the time extension and the GC gets to peak at 24 hours and begins to decline at 48 hours; The three main indicators hormone of HPT axis(TSH,T3,T4) decreased with the increasing of altitude and TRH increased with the increasing of altitude, compared with the control group and the same elevation of 0 hours, there were statistical significances(P<0.05 or P<0.01); Compared with the control group, the water content of rat lung and brain tissue were increased, there were statistically significances(P<0.05 or P<0.01),with the time extension, the water content increased obviously.The tesis and epididymis indexs were decreased but without statistical significance(P>0.05). The hypoxia groups showed obvious lung and brain edema, as the extension of altitude and hypoxic exposure time, the edema more obvious; The expression of HIF-1?m RNA?VEGF m RNA increased with the increasing of altitude.There were statistical significances compared with the control group and the same elevation of 0 hours(P<0.05 or P<0.01); The levels of T and E2 were decreased with the increasing of altitude.There were statistical significances compared with the control group and the same elevation of 0 hours(P<0.05 or P<0.01); The levels of RBC and HGB were increased with the increasing of altitude.There were statistically significances compared with the control group and the same elevation of 0 hours(P<0.05 or P<0.01).Conclusion:(1)With the increasing of altitude, HPA axis stress reaction are abnormally enhaced and the HPT axis is restrained, which suggests that HPA/ HPT axis regulating function may play an important role in maintaining physiological steady effect at plateau hypoxia environment.(2) The contents of VEGF and HIF-1 ? m RNA ?VEGFm RNA increased, which suggests that VEGF may affect the pathogenesis and provides a certain basis theoretical for the prevention and cure high altitude pulmonary edema and high altitude cerebral adema.(3) The function of gonad is suppressed and the number of red blood cells compensatory increased at plateau hypoxia environment,which prompting the plateau hypoxia environment has a severe impact on the body in order to adapt the environment appear compensatory change. |
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