Carbachol阻断亚硒酸钠对离体皮质神经元的致凋亡作用(英文)

Carbachol blocks apoptosis induced by sodium selenite in cultured cortical neurons

在早期工作发现小剂量亚硒酸钠 (Sodiumselenite)对离体皮质神经元的致凋亡作用的基础上 ,观察了在亚硒酸钠致凋亡模型中加入M型胆碱能受体激动剂Carbachol(Carb)能否阻止凋亡过程和相伴随的有关基因表达的改变。结果显示 :①用不同剂量 (0 .0 0 4 ,0 .0 2 ,0 .1,0 .5,2 .5和 12 .5mmol/L)的Carb和 0 .5μmol/L亚硒酸钠共同处理培养的新生小鼠皮质神经元时 ,用琼脂糖凝胶电泳DNA梯形检测和流式细胞仪亚二倍体峰检测 ,都证明Carb表现出对亚硒酸钠致凋亡作用的剂量依赖性保护效应 ;②用RT PCR技术证明 ,在与Carb共同孵育的实验中 ,不再出现或减弱了亚硒酸钠单独处理时出现的bcl 2基因表达的下调和bax ,p53,c fos以及AChE基因表达的上调。上述结果表明 ,亚硒酸钠对皮质神经元的致凋亡作用和与之相伴随的基因表达的改变 ,可被一定浓度的Carb所阻断 ,提示亚硒酸钠致凋亡作用可能同本室发现的 β 淀粉样蛋白的C末端 5肽片段的致凋亡作用具有类似的途径 ,以类似的基因表达改变为基础 ,并对Carb的抗凋亡机制进行了讨论。

On the basis of our previous report that sodium selenite could induce apoptosis in cultured newborn mice cortical neurons, the present study was designed to examine if the apoptotic processes and related gene expression modulations induced by sodium selenite could be affected by coadministration of carbachol. The results showed that:①simultaneous incubation with 0.5μmol/L sodium selenite and different dosages of carbachol (0.004, 0.02, 0.1, 0.5, 2.5, and 12.5 mmol/L) could suppress dose-dependently the intranucleosomal DNA fragmentation induced by sodium selenite alone as revealed by agarose gel electrophoresis examination of DNA ladder formation and flow cytometric examination of hypodiploid peak appearance;②by using RT-PCR assay, coadministration of 2.5 mmol/L carbachol with 0.5 μmol/L sodium selenite could also ameliorate or reverse the down-regulation of bcl-2 and up-regulations of bax, p53, c-fos, and AChE genes as induced when sodium selenite was used alone; It is proposed that coadministration of carbachol could prevent the apoptosis and related alterations in gene expressions induced by sodium selenite alone. For the same results have been obtained in the case of apoptosis induced by β-amyloid fragment reported by us before, it is suggested that these two agents induce apoptosis through a similar pathway and rely on the same alterations in expression of related genes at genomic level.