Objective: To investigate the protective effect of cerebrospinal fluid containing Zhenganxifeng decoction (CSF-ZGXF) on pc12 cell induced by 1-methyl-4-phenylpyridinium ion (MPP+). Method: Neurotoxicity was induced by addition of MPP+ into PC12 cell cultures. And different doses of CSF-ZGXF were administrated 24 h before addition of MPP+ into PC12 cell cutrure. Cell viability

mRNA and protein of Bax and Bcl-2 expression was assayed by MTT

real-time PCR and western blot. Result: Optical density for PC12 cells treated with MPP+ for 48\|96 h was lower than that of the control group. The mRNA and protein expression of Bcl-2 was down-regulated and those of Bax was up-regulated in MPP+ groups compared with the control group. The mRNA and protein expression of Bcl-2 were up-regulated and those of Bax were down-regulated in CSF-ZGXF group compared with the MPP+ group. Conclusion: The results suggest that protective effect of CSF-ZGXF on PC12 cells may correlate with down-regulation of mRNA and protein expression of Bax and up-regulation of those of Bcl-2.