TRPC6在匹罗卡品致痫大鼠海马苔藓纤维出芽中的作用

Effect of TRPC6 on mossy fiber sprouting in hippocampus of rats with pilocapine-induced epilepsy

摘要:

目的 观察传统型瞬时受体电位通道6（TRPC6）蛋白在匹罗卡品致痫大鼠海马中的表达变化，探讨其在海马苔藓纤维出芽中的作用。方法 72只SD大鼠随机分为实验组（n=60）和对照组（n=12）。实验组采用氯化锂－匹罗卡品腹腔注射法建立颞叶癫痫模型；对照组腹腔注射等量无菌生理盐水。实验组按癫痫持续状态（SE）后1 d、7 d、15 d、30 d和60 d分为5个亚组，每亚组12只大鼠。以上各亚组及对照组再分为2个小组，分别进行Western blot检测TRPC6及突触重建标志蛋白Synaptophysin在海马中的表达和Timm染色观察海马苔藓纤维出芽并评分。结果 实验组TRPC6蛋白表达量在SE后1 d达高峰（P<0.01），其他时间点均显著高于对照组（P<0.01）。Synaptophysin蛋白表达量在SE后7 d、15 d、30 d和60 d显著增加（7 d：P<0.05；15 d、30 d、60 d：P<0.01），30 d达峰值（P<0.01）。实验组大鼠齿状回内分子层在SE后7 d出现Timm颗粒，并呈进行性增加。结论 TRPC6可能参与了苔藓纤维出芽这一过程。

Abstract:

Objective To observe the dynamic changes of canonical transient receptor potential channels 6 (TRPC6) expression in the rat hippocampus with pilocarpine-induced epilepsy, and to investigate its effect on mossy fiber sprouting in hippocampus. Methods Seventy-two healthy male Sprague-Dawley (SD) rats were divided randomly into experimental group (n=60) and control group (n=12). The temporal lobe epilepsy model was established by intraperitoneal injection of lithium and pilocarpine, while the controls were injected with equal dose of saline (NS). The experimental rats were equally divided into 5 subgroups at time points 1 day、7 days、15 days、30 days and 60 days after status epileptics (SE). Each subgroup and the control rats were subsequently divided into 2 panels for the following tests respectively: ① expression of TRPC6 and Synaptophysin protein in rats' hippocampus by Western blot; ② Timm staining and score. Results The expression of TRPC6 was markedly increased and reached its peak on 1 days after SE (P<0.01), and it was higher than the control at all the other time points (P<0.01). Compared with the control, the expression of Synaptophysin was markedly up-regulated on 15 days、30 days、60 days after SE (P<0.05 or P<0.01), and reached the peak on 30 days after SE. Timm granules appeared in molecular layer of gyrus dentatus in the hippocampus of experimental rats since 7 days after SE, and then gradually increased. Conclusions TRPC6 may play a potential role in mossy fiber sprouting, in which BDNF may involve.