MDMA神经毒性机制——氧化应激损害的初步研究

A Preliminary Study on the Mechanism of Neurotoxicity of MDMA——Oxidative Stress Harm

目的建立单次给药的长期神经毒性模型,探讨3,4-亚甲基二氧基甲基苯丙胺(MDMA)的神经毒性机制及维生素C(VitC)是否具有MDMA神经毒性的保护作用。方法将雄性Wistar大鼠随机分为对照组(A)和实验组(B、C、D、E),B组给予MDMA20mg/kg,C、D、E组分别在给予MDMA前30min、MDMA后3h、5h给予VitC250mg/kg,A组注射等体积生理盐水。采用高效液相色谱法测定大脑皮层ATP、ADP含量的变化,海马、枕叶皮层神经递质5-HT的含量变化;采用原位杂交方法检测5-羟色胺转运体(SERT)mRNA;免疫组织化学法检测胶质纤维酸性蛋白(GFAP)的表达。结果给予MDMA12h后,与对照组相比,大脑皮层ATP含量明显下降(P<0.05),7d后,与对照组比较,大鼠枕叶皮层、海马的5-HT均有下降(P<0.05),大鼠海马的SERTmRNA的信号表达下降,而脑组织GFAP蛋白的表达则升高(P<0.05)。提前30min和MDMA后3h给予VitC,未能见到对ATP、5-HT功能标志的保护作用(P>0.05),MDMA后5h给予VitC对ATP、5-HT功能标志有保护作用(P<0.05)。给予VitC组对脑组织GFAP蛋白的表达均显示了保护作用(P<0.05)。结论MDMA耗竭大脑皮层直接能源物质ATP,对中枢5-HT系统具有明显的神经毒性。在MDMA后5h给予维生素C,对能源物质ATP和5-HT能系统有保护作用。

Objective Establishing a long-term neurotoxic model to explore the mechanism of neurotoxicity of 3,4-methylenedioxymethamphetamine （MDMA） and the putative protection conferred by Vit C against oxidative stress harm. Methods Male Wistar rats were randomly assigned to control group （A） and MDMA treatment groups（B, C, D, E）. Rats of group B were given MDMA 20 mg/kg; groups C, D, E were given Vit C 250 mg/kg 30 min before administration of MDMA （Vit C 30 min group） and 3 h （Vit C 3 h group） and 5 h （VitC 5 h group） after administration of MDMA,respectively. Rats of control group were treated with the same volume of saline. Concentrations of ATP and ADP in brain cortex and 5-HT in hippocampus and occipital cortex were measured by high perfor-mance liquid chromatography; the expression of SERT mRNA was detected by in situ hybridization; and the expression of protein GFAP was detected by immunohisto-chemistry. Results Twelve hours after MDMA treatment, the concentration of ATP in brain cortex was lessened, compared with control （P〈0. 05）. On the 7th day after MDMA treatment, the concentration of 5-HT in rat hippocampus and occipital cortex was decreased, compared with control （P〈0. 05）. The expression of SERT mRNA in hippocampus was decreased, whereas the expression of GFAP in brain tissue was increased （P〈0. 05）. The adminstration of Vit C 30 min before MDMA treatment and 3 h after MDMA treatment did not curb the decrease of ATP, 5-HT and the expression of SERT mRNA, but Vit C administrated 5 h after MDMA treatment could curb the decrease of ATP and the functional markers of 5-HT. And Vit C given at three time points did downregulate the GFAP expression. Conclusion MDMA could deplete the direct energetic substance ATP. MDMA could exert neurotoxic effect on 5- HT system. Vit C given 5 h after MDMA administration could provide neuroprotection for ATP and 5-HT system.