Abstract: 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 125μmol/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(P<0.05),while the level of GSH in all groups obviously decreased(P<0.01).Compared with the control group,the protein expression level of Nrf 2 in the cytoplasm were significantly decreased(P<0.05).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(P<0.05). Compared with the control group,the protein expression level of PKC-δ was significantly increased(P<0.05).The protein expression level of CKⅡof the high dose group showed a significant elevatation(P<0.05). 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 CKⅡ play certain role in the Nrf 2 activation through increasing expression levels of two proteins stimulated by lead.