Fas对镉暴露致大鼠大脑皮质自噬体形成的影响

为探究死亡受体Fas在镉暴露致大鼠大脑皮质自噬体形成中的作用，将24只21日龄雄性SD大鼠随机分为4组，分别为对照组、镉组、镉与对照病毒共处理组、镉与Fas基因沉默病毒共处理组。试验期间，对照组大鼠自由饮用纯净水，病毒处理组大鼠于第1天以每只1.4×10¹¹vg的剂量通过尾静脉注射相应病毒，4周后镉染毒组大鼠自由饮用镉水(50 mg·L^-1)，持续90 d。试验结束后，透射电镜观察大脑皮质中自噬体数量，Western blot检测大脑皮质细胞外信号调节激酶1/2(Erk1/2)、p-Erk1/2、自噬相关蛋白7(ATG7)、自噬相关基因(Beclin-1)、微管相关蛋白1轻链3(LC3)蛋白表达水平，免疫荧光染色检测LC3表达水平。结果显示，镉暴露增加大脑皮质中自噬体数量，极显著激活Erk1/2并上调ATG7、Beclin-1、LC3蛋白表达水平(P<0.01)；Fas基因沉默抑制镉引起的自噬体数量增加，极显著抑制镉致Erk1/2激活及ATG7、Beclin-1、LC3蛋白表达水平升高(P<0.01)。结果表明，Fas通过激活Erk1/2参与镉致大鼠大脑皮质自噬体形成。

Effects of Fas on Autophagosomes Formation Induced by Cadmium Exposure in Rat Cerebral Cortex

In order to explore the role of death receptor Fas in the autophagosomes formation of rat cerebral cortex induced by cadmium (Cd), twenty-four 21-day-old male SD rats were randomly divided into 4 groups:control group, Cd group, Cd and control virus co-treated group, Cd and Fas gene silencing virus co-treated group. During the experiment, the rats in the control group drank purified water freely. Rats in the virus treatment groups were injected with corresponding virus through the tail vein at a dose of 1.4×10¹¹ vg per rat on the first day. Four weeks later, rats in the Cd-exposed groups received drinking water containing 50 mg·L^-1 Cd freely for 90 days. After the experiment, the number of autophagosomes in the cerebral cortex was observed by transmission electron microscope. The protein expression level of extracellular signal-regulated kinase 1/2 (Erk1/2), p-Erk1/2, autophagy-related protein 7 (ATG7), autophagy related gene (Beclin-1), microtubule-associated protein 1 light chain 3 (LC3) in the cerebral cortex were detected by Western blot. The expression level of LC3 was detected by immunofluorescence staining. The results showed that Cd increased the number of autophagosomes in the cerebral cortex, significantly activated Erk1/2 and up-regulated the protein expression levels of ATG7, Beclin-1 and LC3 (P<0.01). Fas gene silencing inhibited Cd-induced increase of autophagosomes, and significantly inhibited Cd-induced activation of Erk1/2 and upregulation of ATG7, Beclin-1, LC3 protein expression levels (P<0.01). The results indicated that Fas participated in Cd-induced autophagosomes formation by activating Erk1/2 in rat cerebral cortex.