基于免疫激活研究左归降糖解郁方对糖尿病并发抑郁症大鼠海马谷氨酸重摄取的干预作用

Effect of Zuogui Jiangtang Jieyu Formulation on the Reuptake of Glutamic Acid by Hippocampus Based on the Active Immunity in Diabetes-induced Depression Rats

关键词:  左归降糖解郁方  免疫激活  星形胶质细胞  谷氨酸  海马

Key words:  Zuogui Jiangtang Jieyu formulation  immune-activation  astrocyte  glutamic acid  hippocampus

摘要:

目的 研究糖尿病并发抑郁症模型大鼠海马内免疫状态对星形胶质细胞谷氨酸重摄取功能的影响，及左归降糖解郁方对其干预作用。方法 建立糖尿病并发抑郁症大鼠模型，并随机分为模型组、阳性药组（0.18 g·kg^-1二甲双胍+1.8 mg·kg^-1氟西汀）、左归降糖解郁方高、中、低剂量组（20.53，10.26，5.13 g·kg^-1），以正常大鼠为正常对照组，灌胃给药4周。分别采用ELISA法检测各组大鼠血清和海马中白细胞介素-1（IL-1）、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、干扰素-γ（IFN-γ）及海马中谷氨酸含量，采用电镜观察各组大鼠海马血脑屏障结构，采用双重免疫组化技术检测各组大鼠海马星形胶质细胞胶质纤维酸性蛋白（glial fibrillary acidic protein，GFAP）及谷氨酸转运蛋白2（EAAT2）表达。结果 与正常对照组比较，模型组大鼠血清及海马匀浆液中各细胞因子表达均显著升高（P<0.05或P<0.01），电镜结果显示血脑屏障存在一定损伤；海马中GFAP表达显著增加（P<0.05），而EAAT2表达显著减少（P<0.01），海马匀浆液中谷氨酸含量异常增多（P<0.01）。高剂量左归降糖解郁方可显著减少模型大鼠血清中各细胞因子及海马匀浆液中IL-1、IL-6、IFN-γ和谷氨酸的含量（P<0.05或P<0.01），显著降低GFAP并增加EAAT2的表达（P<0.05或P<0.01），此外，其对大鼠海马血脑屏障也具有一定的保护作用。结论 左归降糖解郁方可通过增加糖尿病并发抑郁症大鼠海马星形胶质细胞表面EAAT2表达，减少谷氨酸造成的兴奋性毒性，该作用可能与其抑制模型大鼠脑内免疫激活有关。

Abstract:

OBJECTIVE To investigate the effect of reuptake of glutamic acid by astrocyte based on immune in diabetes-induced depression rats, and the function of Zuogui Jiangtang Jieyu formulation. METHODS Diabetes-induced depression rats were randomly divided into model group, positive drug group(0.18 g·kg^-1metformin+1.8 mg·kg^-1 fluoxetine), Zuogui Jiangtang Jieyu formulation high, medium and low dose group(20.53, 10.26, 5.13 g·kg^-1), while the normal rats belonged to the control group. The levels of IL-1, IL-6, TNF-α, IFN-γ in plasma and hippocampus and the glutamic acid in hippocampus were tested by ELISA after four weeks of intragastric adminitation. The morphological changes of blood-bain barrier were observed in the electron microscope. The expression of GFAP and EAAT2 were detected by double immunocytochemistry. RESULTS Compared with the control group, the levels of four cytokines in plasma and hippocampus and glutamic acid in hippocampus were significantly higher(P<0.05 or P<0.01), and there was obvious damage in BBB. In hippocampus, the expression of GFAP was increased(P<0.05), wihle the EAAT2 was decreased(P<0.01). The Zuogui Jiangtang Jieyu formulation can diminish the level of cytokines in serum and the level of IL-1, IL-6, IFN-γ, glutamic acid in hippocampus, and decreased the expression of GFAP while increased EAAT2 in hippocampus(P<0.05 or P<0.01). CONCLUSION The Zuogui Jiangtang Jieyu formulation can reduce the excitotoxicity of glutamic acid through increasing the expression of EAAT2 in astrocyte, and this function might be correlated with inhibition the immune-activation.