天麻素对脑缺血再灌注小鼠海马新生神经元的保护作用

目的:探讨不同剂量天麻素(Gastrodin,GAS)对缺血再灌注模型小鼠海马新生神经元的保护作用及其可能机制。方法:将50只C57BL/6小鼠随机分为假手术组(Sham)、模型组(MCAO+Vehicle)、模型+天麻素低剂量(10 mg/kg)组(MCAO+GAS(L)),模型+天麻素中剂量(50 mg/kg)组(MCAO+GAS(M)),模型+天麻素高剂量(100 mg/kg)组(MCAO+GAS(H))。除Sham组接受假手术外(皮肤切开,分离颈动脉),分别对MCAO组及MCAO+GAS各组行右侧颈内动脉栓线术,造成并保持大脑中动脉闭塞(MCAO)1 h。术后,Sham组和MCAO组即刻腹腔注射生理盐水(0.1 m L/kg),MCAO+GAS各组注射不同剂量天麻素,每24小时重复给药1次,连续7天。最后一次注射24 h后,对各组小鼠的神经功能进行评分,之后处死动物取脑组织,通过HE、免疫荧光染色以及Western Blot观察和比较各组小鼠海马形态学和DCX的表达水平。结果:(1)术后第7天,MCAO+Vehicle组小鼠神经功能评分(3.2±0.63)显著高于假手术组、MCAO+GAS(M)(1.8±0.63)和MCAO+GAS(H)组(P0.05)。(2)术后第7天,与假手术组相比较,MCAO+vehicle组海马颗粒细胞排列不规则,核稍大且固缩深染,齿状回部有较多空洞;与MCAO+vehicle组比较,MCAO+GAS(H)组海马空洞样改变减少,细胞排列较整齐,胞膜较完整,核结构较清晰。(3)术后第7天,与假手术组相比较,DCX染色阳性细胞数显著减少,而MCAO+GAS(M)组DCX染色阳性细胞数(183±64.5)和MCAO+GAS(H)组DCX染色阳性细胞数(195±93.68)显著高于MCAO+Vehicle组。MCAO+Vehicle组海马的DCX表达水平显著低于假手术组及MCAO+GAS(M)组和GAS(H)组(P0.01)。结论:天麻素可能通过上调海马DCX的表达水平,调节海马神经发生,进而对缺血性脑卒中后再灌注发挥神经保护作用。

Protective Effects of Gastrodin on the Hippocampal Newborn Neurons afterCerebral Ischemia-Reperfusion

Objective:To observe the effects of different concentrations of gastrodin (GAS) on the neural function and theexpression of DCX in the hippocampus after cerebral ischemia-reperfusion in mice.Methods:50 male C57BL/6J mice were randomlydivided into five groups: Sham, MCAO+Vehicle, MCAO+GAS (L, L=10 mg/kg), MCAO+GAS (M, M=50 mg/kg), MCAO+GAS (H,H=100 mg/kg). The mice in Sham group received fake surgery, while the mice in MCAO and MCAO+GAS group were exposed toMCAO. Mice were injected intraperitoneally with saline or different doses of GAS 1 h after surgery once daily for 7 consecutive days,and then the neural function scores were assessed before execution. The hippocampal structure was observed by hematoxylin-eosinstaining and immunohistochemistry, and the expression of DCX was also detected byWestern blotting.Results:(1) The neural functionscore in MCAO+Vehicle group (3.2± 0.63) was higher than that of Shamand MCAO+GAS (M) (1.8± 0.63) or MCAO+GAS (H) groupon the 7th day after reperfusion (P<0.05). (2) Compared to Sham group, hippocampal granule cell layer was arranged irregularly inMCAO+Vehicle group on the 7th day after reperfusion, there also appeared pyknosis and void like changes. The void like changes werereduced and granule cell layer was more clear in MCAO+GAS (H) group in comparison with MCAO+Vehicle group. (3) Afterreperfusion, MCAO+Vehicle group showed less number of DCX positive cell in comparison with Sham group. Moreover, MCAO+GAS(M) group (183± 64.5) and MCAO+GAS (H) group (195± 93.68) showed more number of DCX positive cell in comparison withMCAO+Vehicle group on the 7th day. Consistent with the result of immunohistochemistry, the expression of DCX in MCAO+Vehiclewas significantly less than that of Sham, MCAO+GAS (M) and MCAO+GAS (H) groups (P<0.01).Conclusion:Gastrodin could regulateneurogenesis by up-regulating the expression of DCX in hippocampus of MCAO mice, reduce its neurologic impairment in a certain does, and show some protect effects of cerebral ischemia.