JAK/STAT信号转导通路在IGF-1抑制左旋多巴诱导的多巴胺能神经元凋亡中的作用  

Insulin-like growth factor 1 protects dopaminergic neurons from L-dopa-induced toxicity via JAK/STAT pathway

作　　者：贺荣霓[1] 谢惠芳[1] 刘振华[1] 颜振兴[1] 蔡卫卫[1] 辛倥[1] 

机构地区：[1]南方医科大学珠江医院神经内科,广州510282

出　　处：《中华神经医学杂志》2011年第5期475-479,共5页Chinese Journal of Neuromedicine

摘　　要：目的 探讨胰岛素样生长因子1（IGF-1）通过JAK/STAT信号转导通路对左旋多巴诱导的多巴胺能神经元凋亡的保护作用.方法 应用100μg/L β神经生长因子（β-NGF）将体外常规培养的PC12细胞诱导分化为多巴胺能神经元.MTT比色法筛选左旋多巴的神经损伤浓度和IGF-1的神经保护浓度（150μmol/L、100nmol/L）,实验分为4组：（1）左旋多巴＋IGF-1组;（2）左旋多巴＋IGF-1＋AG490组,AG490（10 μmol/L）在给予左旋多巴和IGF-1前20 min加人;（3）左旋多巴组;（4）对照组.Western blotting检测4组细胞P-JAK2、P-STAT3蛋白表达,Hoechst33258染色和流式细胞仪分别检测细胞凋亡和凋亡率.结果 Westen blotting法检测显示对照组和左旋多巴组P-JAK2、P-STAT3蛋白表达阴性,而左旋多巴＋IGF-1组和左旋多巴＋IGF-1＋AG490组表达阳性.左旋多巴＋IGF.1＋AG490组P.JAK2、P.STAT3表达强度低于左旋多巴＋IGF.1组,差异有统计学意义（P〈0.05）：Hoechst33258染色结果显示左旋多巴组细胞核固缩及碎裂最明显,较多凋亡小体形成,而左旋多巴＋IGF-1组与左旋多巴＋IGF-1＋AG490组仅有少量凋亡小体形成.流式细胞仪检测显示4组多巴胺能神经元凋亡率不同,差异有统计学意义（F=180.991,P=0.000）;与对照组比较,另3组细胞凋亡率均增高,差异有统计学意义（P〈0.05）;其中左旋多巴组细胞凋亡率最高,其次为左旋多巴＋IGF-1＋AG490组、左旋多巴＋IGF-1组.结论 大剂量左旋多巴对多巴胺能神经元具有毒性作用.IGF-1对左旋多巴诱导的神经细胞毒性作用呈保护作用,JAK2/STAT3信号转导通路参与了此过程.Objective To explore the protective effect of insulin-like growth factor 1 （IGF-1） on apoptosis of dopaminergic neurons induced by L-dopa via JAK/STAT signaling pathway. Methods PC12 cells were induced to differentiate into dopaminergic neurons with 100 μg/L β-NGF; MTT assay was employed to identify the changes in the viability of PC12 cells following L-dopa treatment at 0, 10,20, 50, 100, 150 and 200 μmol/L, and the different concentrations of IGF-1 at 0, 10, 25, 50 and 100 nmol/L with the same concentration of L-dopa （150 μmol/L）; Western blotting was used to detect the levels of P-JAK2/P-STAT3 in PC12 cells treated with PBS （controls）, L-dopa, L-dopa＋IGF-1 and L-dopa＋IGF-1＋AG490 for 24 h, and then the apoptosis rate was assessed by flow cytometry and Hchest33258 staining. Results Western blotting showed that the expressions of P-JAK2 and P-STAT3 were detected in the L-dopa＋IGF-1 and L-dopa＋IGF-1＋AG490 treatment groups but not in the control group or L-dopa treatment group; the expression of P-STAT3 in the L-dopa＋IGF-1＋AG490 treatment group was obviously lower than that in the L-dopa＋IGF-1 treatment group （P〈0.05）. Hchest33258 staining indicated that L-dopa treatment group had the most obvious karyopyknosis and karyorrhexis,much more apoptotic bodies than the L-dopa＋IGF-1 and L-dopa＋IGF-1＋AG490 treatment groups. Flow cytometry showed that the apoptosis rate was significantly different among the 4 groups （F=180.991,P=0.000）： as compared with the control group, the other 3 groups had a higher apoptosis rate （P〈0.05）;L-dopa treatment group （38.13 ±2.54 %） enjoyed the highest level, followed by L-dopa＋IGF-1 ＋AG490treatment group （25.60±1.30 %） and L-dopa＋IGF-1 treatment group （20.17±1.54 %）. Conclusion L-dopa has toxic effect on PC12 cells; IGF-1 could protect the PC12 cells from the neurotoxic effect of L-dopa and JAK2/STAT3 signaling pathway is activated in this procedure.

关 键 词：帕金森病 JAK/STAT信号转导通路 胰岛素样生长因子1 

分 类 号：R742.5[医药卫生—神经病学与精神病学]