尾悬吊模拟失重大鼠卵巢组织中缺氧诱导因子-1α表达变化

Expression of hypoxia inducing factor-1α in rats' ovary under tail-suspension weightlessness

目的研究模拟失重环境下大鼠卵巢组织中缺氧诱导因子-1α(HIF-1α)的表达变化。方法取性成熟期健康雌性Wistar大鼠60只作为研究对象,体重200±20g,随机分为10组(n=6),按模拟失重时相分为悬吊0.25、0.5、1、2、3、5、7、14、21d组和0d组(对照组)。采用尾悬吊法建立模拟失重动物模型。各组大鼠卵巢组织中HIF-1α的表达分别应用免疫组织化学和RT-PCR方法进行检测。结果各实验组及对照组大鼠卵巢卵泡卵母细胞、颗粒细胞和膜细胞中均可见HIF-1α阳性染色细胞。对照组大鼠卵巢HIF-1α染色阳性颗粒主要位于细胞质中,悬吊0.25d和0.5d组大鼠卵巢卵母细胞、颗粒细胞和膜细胞的HIF-1α颗粒由细胞质向细胞核转移;尾悬吊1d组HIF-1α表达情况与对照组接近,HIF-1α核染色消失。尾悬吊0.25d、0.5d大鼠卵巢HIF-1αmRNA表达水平显著高于对照组(P<0.05),持续尾悬吊1d以后各组卵巢HIF-1α的蛋白和mRNA水平逐渐恢复至对照组水平。结论尾悬吊模拟失重使大鼠卵巢组织中HIF-1α蛋白及mRNA表达发生明显变化,早期同步过表达,提示卵巢HIF-1α表达变化与失重应激反应和失重耐受有密切关系。

Objective To investigate the expression feature of hypoxia inducing factor-1α（HIF-1α） in rats’ ovary under simulated weightlessness.Methods Sixty adult female Wistar rats,weight 200±20g,were randomly divided into 10 groups（6 each）： a control group without simulating weightlessness,and experimental groups underwent tail suspension for 0.25,0.5,1,2,3,5,7,14 and 21-day,respectively.The HIF-1α expression in rats’ ovaries was assessed by immunohistochemical staining and RT-PCR assay.Results Positively stained HIF-1α was observed as brown particle in follicular oocytes,granulosa cells and thecal cells of rat ovaries in both experimental and control groups.The positively stained HIF-1α granules mainly located in the cytoplasm of ovarian cells in control group,while in tail-suspension 0.25-day and 0.5-day groups,the granules transferred from cytoplasm to nucleus of follicular oocytes,granulosa cells and thecal cells.The expression level in tail-suspension 1-day group was similar to that in control group,and the staining of nuclei disappeared.The expression level of HIF-1α mRNA was significantly higher in tail-suspension 0.25-day and 0.5-day groups than that in control group（P〈0.05）.One day after tail-suspension,the expression levels of both HIF-1α protein and HIF-1α mRNA gradually recovered to that of control group.Conclusion The simulated weightlessness by tail-suspension,serving as a kind of stress,may increase the expression of both HIF-1α protein and HIF-1α mRNA in rat ovary during the early period,implying that a close correlation between the HIF-1α expression in rats’ ovary and the weightlessness stress tolerance.