急性低氧条件下复氧后大鼠脑HIF-1α、nNOS蛋白的表达与人参皂甙Rd干预

摘要

目的 观察大鼠脑缺氧状态下缺氧诱导因子1α(HIF-1α)、神经元性一氧化氮合酶(nNOS)蛋白的表达规律及低氧状态下人参皂甙Rd ( Rd)干预对其影响并探讨机理. 方法 将成年Wistar大鼠120只随机分为3组:①急性低氧组(对照组);②低氧预处理组(低氧干预组);③人参皂甙Rd预处理组(药物干预组).每组按照缺氧后不同时间点再分为4个亚组,各亚组10只大鼠,分别观察各组大鼠海马锥体细胞层神经元形态的变化及HIF-1α、nNOS蛋白的表达规律.结果 在缺氧后复氧即刻,我们可以发现HIF-1α、nNOS蛋白的少量表达,主要存在于海马细胞,多在细胞质中表达;随着时间的推移,在复氧后4 h,HIF-1α、nNOS表达渐达高峰,至复氧后9h HIF-1α表达明显减少,而nNOS表达至复氧后24 h明显减少.低氧预处理组及人参皂甙Rd预处理组的实验结果发现HIF-1α、nNOS表达较对照组减少,与急性低氧组各时间点相比,均有统计学意义(P=0.009).两个干预组之间各时间点比较无统计学差异(P＞0.05).结论 急性低氧可以促使HIF-1α、nNOS蛋白在大鼠海马神经细胞的表达,具有时间依赖性;同时低氧预处理及人参皂甙Rd预处理均可促使大鼠脑组织HIF-1α、nNOS表达减少,可能对急性缺氧性脑损伤产生保护作用,其具体机理可能与其抗自由基、抑制Ca2+内流有关%Objective To observe the expression of HIF-1α、nNOS in cerebral hypoxia rats and the effect by ginsenoside Rd interference as well as to explore its possible mechanism. Methods 120 adult wistar rats were divided into 3 groups :①acute hypoxia group②hypoxia pretreatment group③ginsenoside Rd interference group; each group is divided int0 4 sub-groups( 10 rats per sub-group ) as different hypoxic time, to observe the change of hippocampus cell's shape and the expression of HIF-1α、nNOS in every group. Results At immediate reoxygen time, we can found a few expression of HIF-1α、nNOS protein which mostly consisted in hippocampus cell, much of them in cytoplasm; as time processed, the level of HIF-1α 、nNOS gathered the peak at reoxygen 4h; the level of HIF-1α markedly decreased at reoxygen 9h; and the level of nNOS markedly decreased at reoxygen 24h. There is statistical differences for AOD values between control groups and interference groups at every time spot ( P = 0. 009 ).There is no statistical differences between two interference groups at every time spot ( P ＞ 0. 05 )Conclusion Acute hypoxia can cause the expression of HIF-1α 、nNOS in rat hippocampus cells and its expression has time dependence;at the same time, hypoxia pretreatment and ginsenoside Rd interference can make the expression of HIF-1α、nNOS decreased; it suggests that these pretreatment measures may have protective action for acute hypoxia cerebral injury,the regulation of Ca2+ influx and the inhibition of oxygen free radicals may be one of its mechanism.