三七总皂苷对全脑缺血大鼠海马脑水肿及GFAP表达的影响

Effect of total saponins of Panax notoginseng on expression of GFAP in hippocampus and brain water content in rats subjected global cerebral ischemia injury

目的探讨三七总皂苷(TSPN)对全脑缺血后成年大鼠海马胶质纤维酸性蛋白(GFAP)表达及脑水肿的影响。方法采用四血管阻断法制作全脑缺血模型,大鼠被随机分成假手术组、模型组和TSPN组。TSPN组大鼠全脑缺血后30 min ip 75 mg/kg TSPN,每天1次,假手术组和模型组ip给予等体积的生理盐水,连续14 d。分别于再灌注1、3、7、14 d后处死。采用干湿法计算各组大鼠脑组织含水量,免疫组织化学染色观察海马齿状回(SGZ)区GFAP的表达,免疫荧光双标观察SGZ区GFAP/DCX的共表达情况,免疫印迹技术检测海马CA1区GFAP蛋白表达水平。结果 TSPN组大鼠脑组织含水量显著低于模型组(P<0.05);TSPN组、模型组SGZ区GFAP+细胞密度值在3、7、14 d有统计学差异(P<0.05);两组SGZ区GFAP/DCX共表达细胞与DCX阳性表达细胞数目的比值在第7、14天差异显著(P<0.05);免疫印迹结果显示TSPN组海马CA1区GFAP蛋白表达水平在第3、7、14天显著高于模型组(P<0.05)。结论 TSPN可通过促进全脑缺血后大鼠SGZ区星形胶质细胞活化、促进神经再生、减轻脑水肿而发挥神经保护作用。

Objective To explore the effect of the total saponins of Panax notoginseng（TSPN） on the expression of GFAP in hippocampus and brain water content in rats subjected global cerebral ischemia injury. Methods Using four-vessel occlusion method built the global cerebral ischemia model. Rats were divided into Sham group, vehicle group, and TSPN group. The rats in the TSPN group were administered TSPN intraperitoneally 30 min post-brain ischemia. The dose of TSPN（75 mg/kg） was suspended in 0.9% saline, once per day for days 1, 3, 7, and 14 after reperfusion. While rats in the vehicle group was treated with equal volume of 0.9% saline, one injection per day until the rats were sacrificed at either days 1, 3, 7, and 14 after brain ischemia. The brain water content was detected by dry-wet technique and GFAP expression in the dentate subgranular zone（SGZ） was assessed by immunohistochemistry. Moreover, immunofluorescence was applied to detect the GFAP/DCX in the SGZ, and western-blot was adopted to test the protein level of GFAP. Results The brain water content in the TSPN group was significantly lower than the vehicle group（P〈0.05）; There was statistical difference in the GFAP＋ cells density in SGZ at the 3 th, 7 th, 14 th day in two groups（P〈0.05）. Furthermore, compared with the vehicle group, the ratio of the GFAP/DCX to DCX in the SGZ at 7 th, 14 th d of TSPN group was significantly different（P〈0.05）, and the protein level of GFAP on days 3, 7, 14 in the TSPN group was higher（P〈0.05）. Conclusion TSPN could play a neuroprotective effect through promoting gliosis, neuroregeneration in the SGZ, and alleviating brain water content of rats following global cerebral ischemia.