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目的 通过低 G重复暴露的预适应作用 ,来诱导热休克蛋白 70 (HSP70 )表达 ,以探讨预刺激的适宜强度。 方法 SD大鼠 80只 ,随机分为正常对照组 (5只 )和 +4 Gz重复暴露 (+4 Gz/3min,3次 / d) 1d、3d和 5 d组 (每组 2 5只 ) ,分别于暴露后 6 h、1d、2 d、4d和 6 d处死取脑 ,做冰冻切片 ,进行免疫组织化学染色 ,观察 HSP70的表达水平。 结果 各实验组 +4 Gz/ 3m in重复暴露后HSP70在皮层、海马、丘脑和丘脑下部等部位的表达均有明显的时相特点。暴露后 6 h各部位均有轻中度的 HSP70阳性反应 ,暴露后 1d表达至峰值 ,2～ 3d后开始明显减弱。从表达部位看 ,HSP70阳性反应在顶叶皮层、梨状皮层和丘脑下部表达较强 ,丘脑次之 ,海马较弱。各组 HSP70表达峰值虽均在暴露后 1d,但暴露 1d组 2 d后强度明显减弱 ,而暴露 3～ 5 d组在 2 d后仍然维持较高水平 ,即除海马外 ,各脑区在暴露后第 6天仍有较高的表达 ,均未恢复至正常对照水平。 结论 多天低 G重复暴露诱导的 HSP70表达较 1d重复暴露组的表达更强 ,持续时间更长
Objective To induce the expression of heat shock protein 70 (HSP70) through the preconditioning of low G repeated exposure to investigate the appropriate intensity of pre-stimulation. Methods Eighty SD rats were randomly divided into normal control group (n = 5) and +4 Gz repeated exposure (+4 Gz / 3 min, 3 times / d) The brains were sacrificed at 6 h, 1 d, 2 d, 4 d and 6 d after exposure respectively. Frozen sections were obtained and immunohistochemically stained to observe the expression of HSP70. Results The expressions of HSP70 in the cortex, hippocampus, thalamus and hypothalamus were significantly different after repeated exposure of +4 Gz / 3m in each experimental group. 6 h after exposure to mild and moderate HSP70-positive in all parts of the expression 1d peaked after exposure, 2 ~ 3d began to significantly reduced. From the expression site, HSP70 positive reaction in the parietal cortex, piriform cortex and the hypothalamus expression was stronger, the thalamus second, the hippocampus weaker. Although the peak expression of HSP70 in all groups were all at 1 day after exposure, the intensity of 2 days after exposure to 1d significantly weakened, while the exposure to 3 ~ 5 days remained high after 2 days, After 6 days, there is still a higher expression, did not return to the normal control level. Conclusions The expression of HSP70 induced by repeated low-G repeated exposure is stronger than that of 1-day repeated exposure group, and it lasts longer