Abstract: Objective To investigate the influence of arsenic poisoning on the expressions of bcl-2,bax apoptosis control gene in renal proximal tubular epithelial cells in rtas.Methods Forty normal SD rats were divided into high and low dose of arsenic poisoning group and control group.The body weights of the rats were 120-150g.There were 15 rats in high and low dose exposure groups,and 10 rats in the control group.The rats in high and low groups were treated with As₂O₃ through drinking water at the doses of 10 and 0.4 mg/kg·d.The control group was given distilled water.Four months after the treatment,the kidney tissue of the rats was collected.Two step immunohistochemistry method,cell number count,and image analyses were used in the study.Results The bcl-2 immunoractive cells decreased and the average gray value gradually increased in arsenic poisoning groups(P< 0.05).The bax immunoractive cells of renal proximal tubular epithelial were increased and the average gray value decreased(P< 0.05) in arsenic poisoning groups compared to those of the control group.Conclusion The expression of bcl-2,bax apoptosis control gene are involved in the process of apoptosis of renal proximal tubular epithelial cells in arsenic poisoning rats.