芹菜素对脑缺血再灌注大鼠半暗区小胶质细胞表达和脑含水量的影响

Effect of Apigenin on the Expression of Microglia in Penumbra and Cerebral Water Content after Focal Cerebral Ischemia-reperfusion Injury in Rats

目的观察芹菜素对脑缺血再灌注大鼠半暗区小胶质细胞数量、脑组织含水量的影响。方法采用改良线栓法建立大鼠局灶性脑缺血再灌注模型。动物随机分为假手术组、模型组、芹菜素组。模型组和芹菜素组按再灌注后时间不同又分为再灌注24h组、48h组、72h组、7d组,共9组,每组12只。在脑缺血时和脑缺血后的12h大鼠尾静脉各注射1次罗丹明(6g)。芹菜素组于再灌注时及其后每24h腹腔注射11.6×10-3mol/L芹菜素溶液25mg/kg(0.8mL/100g),假手术组和模型组在相同时间注射等体积生理盐水。各组随机取6只,凝集素荧光(FITC-ILB4)组化染色激光扫描共聚焦显微镜观察半暗区小胶质细胞数量的变化;另6只取脑组织测定脑含水量。结果脑缺血再灌注24h,模型组脑缺血半暗区周围出现ILB4阳性表达细胞即小胶质细胞,48h明显增多,72h表达到高峰,7d下降;芹菜素组ILB4阳性表达小胶质细胞在24、48、72h及7d时较模型组明显减少(P<0.05或P<0.01)。脑缺血48、72h,芹菜素组大鼠脑组织含水量明显低于模型组(P<0.01)。芹菜素能有效降低模型鼠24、48、72h及7d的神经功能缺损评分(P<0.05),明显减轻脑损伤程度。结论芹菜素减轻脑缺血再灌注损伤后脑水肿作用可能与其下调小胶质细胞数量的表达、抑制其过度活化密切相关。

Objective To study the effect of apigenin on the expression of microglla in penumbra and cerebral water content after acute transient focal cerebral ischemia-reperfution injury in rats. Methods The acute transient focal cerebral ischemia-reperfusion model was established by modified thread-occlusion method. One hundred and eight male Sprague-Dawley rats were randomized into 9 groups： sham-operated group （group S, n=12）, model groups （group M 24 h, group M 48 h, group M 72 h, group M 7 d, n=12） and apigenin-treated groups （group A 24 h, group A 48 h, group A 72 h, grouop A 7 d, n = 12）. For monocyte labeling, Rhodamine 6 g was retrogradely injected through the tail artery at the start of the surgery, and was repeated after the first 12 hours. Group A was intraperitineal injected by apigenin 25 mg/kg at the beginning of reperfusion and then every 24 hours following reperfusion respectively. Group S and group M were injected by equal volume of NS at the same time following reperfusion. The neurological behavior scores were valued. Six animals of every group were killed by cervical dislocation under observation the prescriptive time after reperfusion. Water content were measured. Six animals of every group were transcardial perfused and fixated to study the invading monocytes and brain-derived microglia by FITC-islectin B4 histochemistry under CLSM. Results The positive cells of ILB4 （microglia cells） were found in ischemic area after 24 h ischemia and reperfusion in model group. It was increased significantly after 48 h reperfusion and increased to the maximum after 72 h reperfusion, and decreased after 7 day reperfusion. Compared with model group, the expression of microglia cells in apigenin-treated group was decreased at 24, 48 h, 72 h and 7 d （P〈0.05 or P〈0.01）. The cerebral water content in apigenin-treated group was markedly lower than that in model groups after 48 h and 72 h ischemia （P 〈 0.01）. Abnomal neurological behavior scores were lower in apigenin-treated group than the model group of every time （P〈0.05）. Conclusion The apigenin can mitigate brain edema and promote neural function recovery, maybe it is related with down-regulating the expression of microglia cell.