尾吊对大鼠海马组织学习记忆及凋亡相关蛋白表达的影响

Effects of Tail-suspension on Memory and Apoptosis Related Protein Expression in Rat Hippocampus

目的研究尾吊模拟失重效应对大鼠海马神经元形态数目和学习记忆相关分子NMDAR2A,BDNF及促凋亡相关分子Bax,Caspase-3表达的影响,探讨模拟失重所致大鼠学习记忆能力下降的机制。方法24只8周龄SD大鼠随机分为对照组及模拟失重组,每组12只,采用30°尾吊方法模拟失重效应。采用HE及尼氏染色观察模拟失重效应对海马神经元数目形态的影响;采用Western blot检测模拟微重力效应对NMDAR2A,BDNF,Bax,Caspase-3蛋白表达的影响。结果 HE染色及尼氏染色结果发现,尾吊大鼠海马组织神经元数目显著低于对照组,同时其形态也发生了一定的改变。Western blot实验结果显示,与对照组相比,尾吊大鼠海马组织NMDAR2A、BDNF蛋白表达水平显著降低,Bax,Caspase-3蛋白表达水平显著提高。结论尾吊模拟失重效应可影响大鼠海马神经元形态与数目,下调学习记忆相关分子表达,上调促凋亡相关分子表达。

Objective To explore the effects of simulated weightlessness on the neuronal morphology and expression of NMDAR2 A,BDNF,Bax and caspase-3 in rat hippocampus. Methods Twenty-four healthy male 8-week-old Sprague-Dawley（ SD） rats were randomly assigned to control group and simulated weightlessness group,12 rats for each group,and 30° tail-suspension（ TS） rat models were employed to simulate weightlessness. The effects of simulated weightlessness on neuronal cytomorphology were identified with HE staining and Nissl staining. The effects of simulated weightlessness on the expression of NMDAR2 A,BDNF,Bax and Caspase-3 protein was examined with western blot. Results HE staining and Nissl staining indicated that the number of hippocampal neurons was decreased after 28 d of simulated weightlessness compared with the control,and cytomorphological changes were also found in hippocampus neurons of tail-suspension rats. The results of western blot displayed that the expression of NMDAR2 A,BDNF was significantly decreased while the level of Bax and Caspase-3 was significantly increased in rat hippocampus after simulated weightlessness.Conclusion Simulated weightlessness can reduce the quantity of neurons and lower memory related protein expression whereas the level of apoptosis related protein were upregulated in rat hippocampus.