人参皂苷Rg1对癫痫大鼠海马神经元损伤和小胶质细胞活化的影响

目的探讨人参皂苷Rg1对癫痫大鼠海马神经元损伤和小胶质细胞活化的影响及其作用机制。方法 SD大鼠分为对照组(control组)、癫痫模型组(model组)、人参皂苷Rg1低剂量组(Rg1-L组)和人参皂苷剂量组(Rg1-H组),采用氯化锂-匹罗卡品腹腔注射制备癫痫大鼠模型;记录各组大鼠行为学发作情况;ELISA检测各组大鼠海马组织的氧化应激水平;qRT-PCR检测各组海马组织中炎症因子的表达;HE染色观察各组大鼠海马神经元结构和病理形态变化;免疫荧光组织化学染色检测各组大鼠小胶质细胞中iNOS、Arg-1蛋白表达。结果 model组大鼠症状达到Ⅲ级及Ⅲ级以上较control组显著增加,人参皂苷Rg1使大鼠的癫痫症状得到改善;与control组相比,model组大鼠海马组织中MDA(P<0.001)、TNF-αm RNA(P<0.001)、IL-1βmRNA(P<0.001)的表达水平上调,SOD(P<0.001)、IL-10 m RNA(P<0.001)的表达水平下调,而人参皂苷Rg1使大鼠海马组织中MDA(P<0.05)、TNF-αm RNA(P<0.05)、IL-1βmRNA(P<0.05)的表达水平下调,SOD(P<0.05)、IL-10 mRNA(P<0.05)的表达水平上调;model组大鼠海马神经元形态不完整,细胞间间隙增大和排列紊乱,人参皂苷Rg1组大鼠海马神经元形态明显改变,可见细胞排列较规则,大部分细胞形态正常;model组大鼠海马神经元凋亡率显著上升(P<0.001),人参皂苷Rg1组使大鼠海马神经元凋亡率下降(P<0.05);与control组相比,model组大鼠小胶质细胞数量显著增加(P<0.001),iNOS蛋白的表达显著升高(P<0.001),Arg-1蛋白表达显著降低(P<0.001),与model组相比,人参皂苷Rg1组大鼠小胶质细胞数量减少(P<0.05),iNOS蛋白的表达降低(P<0.05),Arg-1蛋白表达升高(P<0.05)。结论人参皂苷Rg1降低癫痫大鼠海马组织中iNOS蛋白的表达,增加Arg-1蛋白的表达,抑制小胶质细胞的激活,减轻氧化应激和炎症因子的表达,降低癫痫大鼠发作的等级。

Effects of ginsenoside Rg1 on hippocampal neuron damage and microglial activation in epilepsy rats

To investigate the effect of ginsenoside Rg1 on hippocampal neuron damage and microglia activation in epilepsy rats and its mechanism of action. SD rats were recruited and divided into control group(control group), epilepsy model group(model group), Ginsenoside Rg1 low dose group(Rg1-L group) and Ginsenoside high dose group(Rg1-H group).Rat model of epilepsy was prepared by intraperitoneal injection of rocapin. The behavior of rats in each group was record;the level of oxidative stress in hippocampus of each group was detected by ELISA.qRT-PCR was used to detect the expression of inflammatory factors in hippocampus of each group;HE staining was used to observe the structure and pathological changes of hippocampal neurons in each group. Immunofluorescence histochemical staining was used to detect iNOS and Arg-1 protein expression in rat microglia. Data showed that the symptoms of epilepsy in model group were reached at least grade III, which were significantly higher than those in control group, and were alleviatedby ginsenoside Rg1 in ginsenoside Rg1 groups. Compared with the control group,the expression levels of MDA(P<0.001), TNF-αmRNA(P<0.001), and IL-1β mRNA(P<0.001) were up-regulated in the hippocampus of the model group,and the expression levels of SOD(P<0.001), IL-10 mRNA(P<0.001) were down-regulated, while ginsenoside Rg1 could reverse these changes. Furthermore,ginsenoside Rg1 also improved the morphological changes in hippocampal neurons of model rats, such as incomplete morphology, increased intercellular space, and disordered arrangement. The apoptosis rate of hippocampal neurons in the model group increased significantly(P<0.001), and the apoptosis rate of hippocampal neurons in the ginsenoside Rg1 group decreased(P<0.05). Compared with the control group, the number of microglia in the model group was significantly increased(P<0.001), the expression of iNOS protein was significantly increased(P<0.001),and the expression of Arg-1 protein was significantly reduced(P<0.001), which could be reversed by ginsenoside Rg1. In conclusion, ginsenoside Rg1 reduces the expression of iNOS protein in the hippocampus of epileptic rats,increases the expression of Arg-1 protein, inhibits the activation of microglia, reduces oxidative stress and inflammatory factors expression, thus reduces the level of seizures in epileptic rats.