Abstract: Objective To observe the effects of n-hexane on the expression of apoptosis regulator genebcl-2, bax, bcl-xl, and xiap mRNA in rato varian granulosa cells.Methods Totally 48 adult female rats were randomly assigned to four groups based on weight and were exposed to 0, 3.01, 9.03, and 27.1 g/m³ n-hexane for 6 weeks(4h/d, 6 days/week), respectively.After n-hexane inhalation, the rats in estrus stage were killed and their ovarian granulosa cells were collected.The expressions of bcl-2、bax, bcl-xl, and xiap mRNA were measured with realtime fluorescence quantita tive PCR m ethod.Results With the increased n-hexane concentration, the expression of bcl-2 mRNA decreased(the value of 2^-△△CT was 1.069, 0.762, 0.698, 0.690, respectively) and the expression of bax mRNA increased gradually (the value of 2^-△△CT was 1.039, 1.242, 1.317, 1.895, respectively), both of them in n-hexane groups showed significant difference compared with those of in the control group (P<0.05).The bcl-xl mRNA expression in all n-hexane groups showed no significant difference compared with that of the control group (P> 0.05).The expression of xiap mRNA in 27.1g/m³ group(the value of 2^-△△CT was 0.694) decreased significantly compared with that of in the control group(the value of 2^-△△CT was 0.999, P<0.05).Conclusion N-hexane could enhance bax mRNA expression and downregulate bcl-2 and xiap mRNA expression, which might be the mechanism of apoptosis of rat ovarian granulosa cell.