甲基汞对大鼠脑一氧化氮合酶,丙二醛和即刻早期基因的影响

为了寻找甲基汞神经毒性检测和评价效应指标以及探讨甲基汞神经毒性分子机制,对大鼠进行氯化甲基汞(MMC)急性暴露(对照组为0.9％生理盐水、暴露组浓度为0.05mg/kg),20min后对大鼠进行生理生化指标和即早基因的检测,大鼠大脑中枢神经系统的神经递质一氧化氮合酶活力采用一氧化氮合酶(NOS)测定试剂盒检测;自由基脂质过氧化产物丙二醛含量采用硫代巴比妥酸(TBA)比色法检测;即刻早期基因c-fos表达的变化采用免疫组化方法检测。结果表明,在暴露氯化甲基汞(MMC)20min后,大鼠大脑中枢神经系统的一氧化氮合酶活力、自由基脂质过氧化产物丙二醛含量以及即刻早期基因(IEG)c-fos蛋白阳性表达数量都有提高。但其中一氧化氮合酶活力及自由基脂质过氧化产物丙二醛含量同对照组相比没有显著性差异;而即刻早期基因c-fos的阳性表达同对照组相比有极显著性差异(P<0.01)。据此可以推测,即刻早期基因能作为甲基汞神经毒性检测和评价效应指标,一氧化氮合酶、丙二醛和即刻早期基因在甲基汞神经毒性过程中具有重要作用。

Study of NOS, MDA and immediate-early gene in rats' brain induced by methyl mercury

To find the biomark of methylmercury (MMC), we investigate the effect of MMC (The control group was physiological saline of 0.9%, the concentration of exposure groups were 0.05mg/kg respectively, the sampling time was 20 min) on the neurotransmitter: the vigor of NOS following the protocol of the kit (purchased from Nanjing Jiancheng Bioengineering Institute); on the free radical: MDA measured by TBA method and on the immediate-early gene (IEG): c-fos measured by immunocytochemistry. From the results, we find that after exposing for 20 min, the vigor of NOS, the content of MDA and the quantity of c-fos protein positive expression were all increased. And compared with the control group, the vigor of NOS and the content of MDA has not difference while the expression of c-fos has significant difference (P<0.01). From the analysis we learn that induced by MMC in the rat's brain, the neurotransmitter maybe impact on the target cell as the first messenger. And then activate the free radical as the second messenger. The second messenger then induced the immediate-early gene (IEG) as the third messenger. So we estimate that the immediate-early gene (IEG) could be the biomark of MMC.