Abstract: ObjectiveTo investigate the effect of sodium arsenite combined with cigarette smoke solution on expression of Bcl-2 and Bax in rat lymphocytes and study their interaction.MethodsAccording to 2×2 factorial design,rat lymphocytes were divided into 4 groups:sodium arsenite treated group,cigarette smoke solution tr eated group,sodium arsenite and cigarette smoke solution treated group and control group.After the exposure,protein expression of Bcl-2 and Bax in rat lymphocytes was detected by western blotting;Apoptosis of rat lymphocytes was detected by flow cytometry.ANOVA of 2×2 factorial design was used to evaluate the interaction.ResultsWhen sodium arsenite treatment and cigarette smoke solution treatment were used together or separately,protein expression of Bcl-2 decreased;Protein expression of Bax and the number of apoptotic cells increased.ANOVA of the factorial design showed that sdium arsenite and cigarette smoke solution had interactions on protein expression of Bcl-2,Bax and the number of apoptotic cells.The interactions were synergistic.ConclusionSodium arsenite and cigarette smoke solution have interactions on protein expression of Bcl-2 and Bax.The interactions are synergistic.