Abstract: ObjectiveTo investigate the combined neurotoxicity effect of 2, 2; 4, 4=tetrabromodiphenyl ethers(PBDE-47) and 2, 2; 4, 4; 5, 5=hexachlorobiphenyl (PCB 153) and its mechanism in SD rats.MethodsThe toxic SD rats models of PBDE-47 or/and PCB 153 were prepared by the treatment of different concentrations of PBDE-47(1, 5,10mg/kg·bw) or/and PCB 153 (5mg/kg·bw).The changes of spatial learning and memory ability of 2-month-old SD rats were investigated by the Morris watermaze experiment Then the mRNA expression levels of DAPK, XIAP, caspase-12, caspase-3, and cytochrome C in hippocampus of the rats were examined by real-time RT-PCR.ResultsWith the increase of PBDE-47 dose, the spatial learning and memory ability of the rats showed a trend of decline, and significant difference existed in all dose groups compared with the control(P<0.05).Meanwhile, PCB 153 could enhance the neurotoxic effects induced by PBDE-47.Comparedwith the control, the mRNA expression level of XlAP was significantly decreased (P<0.05),and them RNA expression levels of caspase-12, caspase-3, and cytochrome Cof male and female SD rats as well as the DAPK of male SD rats were increased in 10mg/kg·bw of PBDE-47 group(P<0.05).Except the DAPK of both male and female rats and the cytochrome Coffemale rats, the interaction between PBDE-47 and PCB 153 existed in the influence of mRNA expression level of other genes(P<0.05).ConclusionPBDE-47 could result in nervous system injury of SD rats, and influence the mRNA expression level of apoptotic pathway-associated genes induced by calcium signaling in hippocampus of SD rats PCR 153 could enhance the neurotoxic effects of PRDE-4Z.