大黄酚对脑缺血损伤模型大鼠小胶质细胞活化及炎症因子表达的影响

Effects of Chrysophanol on the Activation of Microglia and the Expression of Inflammatory Factors in Cerebral Ischemia Model Rats

目的:研究大黄酚对脑缺血损伤模型大鼠小胶质细胞活化及炎症因子表达的影响。方法:将SD大鼠随机分为假手术组、模型组和大黄酚高、中、低剂量组[7.88、3.94、1.97 mg/(kg·d)],每组20只(复制模型过程中如死亡或造模不成功则补足)。除假手术组外,其余各组大鼠均采用改良线栓法建立中动脉闭塞模型。于缺血2 h后,假手术组和模型组大鼠腹腔注射生理盐水1 mL,各给药组大鼠腹腔注射相应药液1 mL,每日1次,连续给药7 d。末次给药后,记录各组大鼠神经功能缺损评分,采用TTC染色法观察大鼠脑组织梗死情况并计算脑梗死面积百分比,采用免疫荧光染色法观察大鼠脑缺血半暗带区Iba-1阳性细胞的表达情况,采用Western blotting法检测大鼠脑缺血半暗带区Notch-1、肿瘤坏死因子α(TNF-α)、细胞间黏附分子1(ICAM-1)蛋白的表达情况。结果:假手术组大鼠脑组织未见梗死区域;其脑缺血半暗带区Iba-1阳性细胞较少且呈分枝状。与假手术组比较,模型组大鼠脑组织梗死区域明显;脑缺血半暗带区Iba-1阳性细胞明显增多,且呈阿米巴形或圆形;其神经功能缺损评分、脑梗死面积百分比以及脑缺血半暗带区Notch-1、TNF-α、ICAM-1蛋白的相对表达水平均显著升高(P<0.05)。与模型组比较,大黄酚各剂量组大鼠脑组织梗死区域均有不同程度缩小;脑缺血半暗带区Iba-1阳性表达细胞有所减少;其神经功能缺损评分、脑梗死面积百分比以及脑缺血半暗带区Notch-1、TNF-α、ICAM-1蛋白的相对表达水平均显著降低(P<0.05或P<0.01)。结论:大黄酚对脑缺血损伤模型大鼠具有一定的脑保护作用,可减轻其神经损伤;其机制可能与抑制Notch信号通路介导的小胶质细胞活化及炎症因子的表达有关。

OBJECTIVE:To study the effects of chrysophanol on the activation of microglia and the expression of inflammatory factors in cerebral ischemia model rats.METHODS:SD rats were randomly divided into sham operation group,model group and chrysophanol high,medium,low dose groups[7.88,3.94,1.97 mg/(kg·d)],with 20 rats in each group(the number was complemented in cases of death or unsuccessful modeling during modeling process).Except for sham operation group,middle cerebral artery occlusion model was established in other groups by improved thread method.After 2 hours of ischemia,sham operation group and model group were intraperitoneally injected with 1 mL normal saline,and each administration group was intraperitoneally injected with 1 mL corresponding drug,once a day,for 7 consecutive days.After last medication,the score of neurological impairment was recorded;cerebral infarction of rats was observed by TTC staining,and the percentage of cerebral infarction area was calculated.The expression of Iba-1 positive cells in ischemic penumbra of rats was observed by immunofluorescence staining.The expression of Notch-1,TNF-α and ICAM-1 in the ischemic penumbra of rats were detected by Western blotting assay.RESULTS:In sham operation group,there was no infarction area in the brain tissue,and the Iba-1 positive cells in the ischemic penumbra were few and branched.Compared with sham operation group,the infarction area of cerebral tissue in rats was obvious in model group;the number of Iba-1 positive cells in ischemic penumbra were increased significantly,and they were in amoeba or round shape;the neurological impairment score,the percentage of cerebral infarction area,relative expression of Notch-1,TNF-α and ICAM-1 protein in ischemic penumbra were increased significantly(P<0.05).Compared with model rats,the infarction area of cerebral tissue in each dose group of chrysophanol was reduced to different extent;the number of Iba-1 positive cells in ischemic penumbra was decreased;neurological impairment score,the percentage of cerebral infarction area,relative expression of Notch-1,TNF-α and ICAM-1 protein were significantly decreased(P<0.05 or P<0.01).CONCLUSIONS:Chrysophanol has a certain protective effect on the brain tissue of cerebral ischemia model rats,and can relieve the nerve injury.Its mechanism may be associated with inhibiting the activation of microglia and expression of inflammatory factors mediated by Notch pathway.