右美托咪定对谷氨酸所致PC12细胞损伤的保护作用及其机制

目的 研究右美托咪定(Dex)对谷氨酸所致PC12细胞损伤的保护作用及机制.方法 应用高浓度谷氨酸处理PC12细胞以建立细胞缺氧损伤模型.应用MTT法测定细胞存活率,采用试剂盒分别测定细胞培养液中乳酸脱氢酶释放量,细胞丙二醛含量和超氧化物歧化酶活力,DCFH-DA染色流式细胞仪检测细胞内活性氧水平,Fluo-8染色流式细胞仪检测细胞内钙离子含量,JC-1染色流式细胞仪检测细胞线粒体膜电位.结果 在0.01～100 μmol/L浓度范围内,Dex浓度依赖性地拮抗谷氨酸所致PC12细胞损伤,至100 μmol/L时,细胞存活率达到正常组的(86.6±2.2)％,显著高于模型组(P＜0.01),乳酸脱氢酶释放量为正常组的1.4±0.1倍,显著低于模型组(P＜0.01).1μmol/L Dex预处理谷氨酸损伤的PC12细胞,与模型组相比,能够显著降低丙二醛含量(P＜0.01),提高超氧化物歧化酶活力(P＜0.01),抑制胞内活性氧过度生成(P＜0.01),降低细胞内Ca2+浓度(P＜0.01),稳定细胞线粒体膜电位(P＜0.01).结论 Dex对谷氨酸所致PC12细胞损伤具有保护作用,其机制可能与Dex抗氧化和抑制细胞内钙超载,保护线粒体功能相关.

Protective effect of dexmedetomidine against glutamate-induced cytotoxicity in PC12 cells and its mechanism

Objective To investigate the protective effects of dexmedetomidine (Dex) against glutamate-induced cytotoxicity in PC12 cells and its mechanism.Methods PC12 cells were treated with varying concentrations of dexmedetomidine 1 h before exposure to a high concentration of glutamate.The cell viability was measured by MTT assay,and LDH release,MDA content and SOD activity were measured.The level of ROS was tested by DCFH-DA staining and flow cytometry.The level of intracellular Ca2+ was detected by Fluo-8 staining and flow cytometry,and the mitochondrial membrane potential (MMP) was determined with JC-1 staining and flow cytometry.Results Within the concentration range of 0.01 to 100 μrnol/L,Dex dose-dependently protected PC12 cells against glutamate-induced cytotoxicity.Treatment with 100 μmol/L Dex significantly increased the cell viability to (86.6±2.2)％ of that of the control cells (P＜0.01) and decreased LDH release to 1.4±0.1 folds of the control level (P＜0.01).In PC12 cells exposed to glutamate,Dex pretreatment significantly reduced MDA content (P＜0.01),enhanced SOD activity (P＜0.01),inhibited ROS overproduction (P＜0.01),reduced intracellular Ca2 + level (P＜0.01) and maintained a stable MMP (P＜0.01).Conclusion Dexmedetomidine can protect PC12 cells against glutamate-induced injury possibly in relation with its anti-oxidative activity,inhibitory effect on intracellular calcium overload and protective effect of the mitochondria.