中文摘要：

目的研究神经细胞内核因子E 2相关因子2（Nrf 2）信号通路是否对铅暴露所致的氧化应激产生应答及其可能机制。方法用低、中、高剂量（5、25、125μmol/L）的醋酸铅溶液对人神经母细胞瘤SH-SY 5 Y细胞染毒,用2＇,7＇-二氯荧光黄双乙酸盐（DCFH-DA）探针检测染毒2 h后细胞活性氧（ROS）水平,染毒24 h后用二硫基双硝基苯甲酸（DTNB）比色法检测还原性谷胱甘肽（GSH）水平,western blot法检测蛋白激酶C-δ（PKC-δ）、酪氨酸激酶2（CKⅡ）以及胞浆和胞核中Nrf 2蛋白的表达水平。结果随着染毒剂量增加,低、中、高剂量组ROS含量依次为（559.17±54.56）、（585.50±36.41）、（621.00±29.96）,与对照组（533.50±46.47）比较,中、高剂量组含量明显升高（P〈0.05）;GSH含量依次为（165.39±17.37）、（140.92±14.77）、（84.03±10.31）,与对照组（222.10±14.91）比较,低、中、高剂量组含量均明显降低（P〈0.01）;与对照组比较,低、中、高剂量组胞浆Nrf 2相对灰度值为（0.38±0.09）、（0.27±0.09）、（0.25±0.11）,胞浆Nrf 2表达均明显降低（P〈0.05）;低、中、高剂量组胞核Nrf 2相对灰度值为（1.38±0.50）、（1.55±0.49）、（2.79±1.56）,仅高剂量组胞核Nrf 2蛋白表达明显增高（P〈0.05）。低、中、高剂量组PKC-δ相对灰度值为（1.84±0.46）、（2.55±0.36）、（2.38±0.77）,与对照组比较均明显升高（P〈0.05）;低、中、高剂量组CKⅡ相对灰度值为（1.28±0.32）、（1.34±0.21）、（1.52±0.42）,与对照组比较仅高剂量组表达明显升高（P〈0.05）。结论铅致神经细胞氧化损伤的同时激活胞浆中Nrf 2转移入核内,进而发挥氧化应答,PKC-δ、CKⅡ在铅致Nrf 2激活过程中具有一定作用。

英文摘要：

Objective To investigate the role of NF-E2-related factor 2（Nrf 2） signal pathway in lead-induced oxidative stress in SH-SY5Y cells as well as the possible mechanism.Methods SH-SY5Y cells were exposed to 0,5,25,and 125 μmol/L lead acetate for 24 hours.After harvesting the cells,the level of reactive oxygen species（ROS） was measured by the method of 2＇,7＇-dicholorofluorescin diacetate（DCFH-DA）,and glutathione（GSH） was tested by dithiothymine double-nitrobenzonic acid（DTNB） method.Western blot was used to detect the levels of protein kinase C-theta（PKC-δ）,casein kinase 2（CKⅡ） Nrf 2 in the cytoplasm and nucleus.Results Compared with the control group,the level of ROS of the moderate and high dose group were obviously increased（P0.05）,while the level of GSH in all groups obviously decreased（P0.01）.Compared with the control group,the protein expression level of Nrf 2 in the cytoplasm were significantly decreased（P0.05）.Meanwhile the protein expression levels of Nrf 2 in the nucleus of the high dose group showed a distinct elevatation,which was remarkbly different from that of the control group（P0.05）.Compared with the control group,the protein expression level of PKC-δ was significantly increased（P0.05）.The protein expression level of CK Ⅱ of the high dose group showed a significant elevatation（P0.05）.Conclusion The findings demonstrate that lead can induce a nuclear accumulation of the transcription factor Nrf 2,which indicates the mediation of Nrf 2 in the cellular response against the oxidative stress caused by lead.The results also indicate that PKC-δ and CKⅡplay certain role in the Nrf 2 activation through increasing expression levels of two proteins stimulated by lead.