丙戊酸钠对小鼠全脑缺血后认知功能恢复与海马神经元再生的促进作用

Effects of Valproate on Cognitive Function Recovery and Neuron Regeneration of Hippocampus in Mice After Global Cerebral Ischemia

目的研究丙戊酸钠(valproate acid,VPA)对小鼠全脑缺血(global cerebral ischemia,GCI)后认知功能恢复与海马神经元再生的影响及其作用机制。方法将48只小鼠随机分为4组:假手术组、VPA组、GCI组和VPA+GCI组,每组12只。GCI组和GCI+VPA组给予抽血和双侧颈总动脉夹闭20 min,假手术组和VPA组仅给予切开和缝合处理。术后VPA组和GCI+VPA组腹腔注射VPA 30 mg·kg^(-1)·d^(-1),连续7 d,假手术组和GCI组给予同等剂量生理盐水。通过选择性T迷宫实验测试小鼠空间记忆认知功能的改变;尼氏法染色小鼠海马CA1区神经元,检测其形态学的改变;免疫荧光观察小鼠海马齿状回(dentate gyrus,DG)区DCX阳性细胞数;Western blot法检测海马nNOS、GAP-43蛋白的表达情况。结果 VPA处理后,GCI小鼠在选择性T迷宫中的认知功能得到改善,海马CA1区神经元密度增加,DG区DCX阳性细胞增加,同时,海马中nNOS表达水平下调,GAP-43表达上调。结论 VPA可在小鼠GCI后起到神经保护作用,并促进海马神经元再生,达到改善GCI认知功能的目的,其机制可能与抑制nNOS并促进GAP-43表达有关。

OBJECTIVE To study the effect of valproate(VPA) on cognitive function recovery and hippocampal neuron regeneration after global cerebral ischemia(GCI) in mice and its mechanism. METHODS Forty eight mice were randomly divided into 4 groups: sham group, VPA group, GCI group, GCI+VPA group, 12 mice in each group. GCI group and GCI+VPA group were drew blood and bilateral common carotid artery occlusion of 20 min. The sham group and VPA group were only treated with incision and suture. After operation, VPA group and GCI+VPA group were intraperitoneal injection 30 mg·kg-1·d-1 for 7 d, sham group and VPA group were given the same dose of saline. The changes in cognitive functions such as spatial learning and memory were tested by the selective T maze test. Nissl staining was used to observe the morphological changes in the hippocampal neurons of CA1 in mice;the number of DCX+ cells in the dentate gyrus(DG) region of the hippocampus in mice was observed by immunofluorescence;the expression of nNOS and GAP-43 in hippocampus of the hippocampus were detected by Western blot. RESULTS The correct selection rate of VPA treated mice in the selective T maze after GCI was higher than that in the saline treatment group, and the density of neurons in hippocampal CA1 area in VPA treated mice was higher than that of the saline treatment group, and VPA treated mice DG region DCX positive cells were increased. Compared with the Saline treatment group, the difference was statistically significant(P<0.05). At the same time, the expression level of nNOS in the hippocampus of GCI mice was down regulated by VPA treatment, and the expression of GAP-43 was up. The difference was statistically significant(P<0.05). CONCLUSION VPA can promote the neuroprotective effect and promote the regeneration of neurons after GCI in mice, which can improve the cognitive function of GCI. The mechanism may be related to the inhibition of nNOS related signaling pathway and the promotion of GAP-43 expression.