益母草碱对糖尿病大鼠模型早期海马神经元影响研究

Effect of Leonurine on Hippocampal Neurons in the Early Stage of Diabetic Rat Model

目的研究益母草碱(SCM-198)对链脲佐菌素(STZ)诱导2型糖尿病(DM)大鼠模型早期海马神经元及谷氨酸转运体表达的影响研究。方法高脂饮食5周后,腹腔注射链脲佐菌素建立2型糖尿病大鼠模型,实验分为正常对照组、糖尿病12周模型组及益母草碱干预组,进行模型动物神经行为学指标检测,血清检测空腹血糖(FBG),总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C),空腹胰岛素(FINS),海马组织神经元病理形态变化,Western blot检测相关转运体蛋白表达变化。结果与DM模型组比较,SCM-198干预组动物首次到达平台的时间显著缩短,(P<0.01),在目标象限停留时间明显延长(P<0.05),动物在平台停留时间及穿越平台次数明显高于DM模型组(P<0.05)。SCM-198干预组动物FBG水平显著降低(P<0.05),LDL-C水平降低显著(P<0.01),HDL-C水平升高显著(P<0.01),TC和TG均有降低趋势(P>0.05);与DM组比较,动物体重显著升高(P<0.05),大脑重量变化不大,脑指数显著降低。HE染色结果显示,SCM-198干预组大鼠海马CA1区出现明显恢复迹象,表现为锥体细胞密度加大,层次较清晰,神经元密度明显升高。WB结果显示,SCM-198+DM组GLT1蛋白表达水平显著增加,差异具有统计学意义(P<0.05),vGLUT1蛋白表达水平则显著降低,差异同样具有统计学意义(P<0.05)。RT-PCR通过mRNA水平表达检测验证了WB的结果。结论在早期糖尿病发生发展过程中引起脑组织海马神经元损伤,导致海马组织谷氨酸转运体表达变化;益母草碱干预组作用能激活谷氨酸转运体的表达,缓解海马神经元神经损伤。

Objective To study the effect of Leonurine(SCM-198)on hippocampus neurons and expression of glutamate transporter in early stage of STZ induced type 2 diabetic rat model.Methods The type 2 diabetic rat model was established by intraperitoneal injection of streptozocin after five-week high fat diet.The rats were randomly divided into control group,DM model group and the SCM-198 intervention group.The neurobehavioral index of rats was assessed in all groups.The fasting blood glucose(FBG),total cholesterol(TC),triglyceride(TG),high density lipoprotein-cholesterol(HDL-C),low density lipoprotein-cholesterol(LDL-C)and fasting insulin(FINS)were tested.The histopathological changes of hippocampus neurons were examined by HE staining.The alteration of related transporter protein expression in hippocampus was determined by Western blotting.Results Compared with DM model group,rats in the SCM-198+DM group took a shorter time to reach the platform for the first time(P<0.01),stayed longer in the target quadrant(P<0.05)and platform,and traversed the platform more frequently.The levels of FBG and LDL-C in the SCM-198 intervention group were significantly decreased(P<0.05 and P<0.01 separately).And the levels of TC and TG were also increased(P>0.05).The weight of animals in SCM-198 intervention group increased significantly(P<0.05),and the weight of the brains did not differ much,so the brain index decreased(P<0.05).The result of HE staining showed that there were obvious signs of recovery in the hippocampus CA1 area in the SCM 198 intervention group,which was characterized by increasing density of neurons and pyramidal cells with clear level.According to the result of Western blot,the expression level of GLP1 protein was increased in SCM-198 intervention group,while the vGLUT1 protein was decreased,both with a statistically significant difference(P<0.05).And the RT-PCR showed the same result with the WB method.Conclusion In the early stages of diabetes development,the hippocampus neuron in brain tissue was injured,which led to changes in the expression of glutamate transporter.The intervention of Leonurine had the potential on reduction of nerve damage in hippocampal neurons via adjusting the expression of glutamate transporter.