Abstract: ObjectiveTo explore the effect of chronic arsenic poisoning on the caspase-3 expression in epithelium cells of proximal convoluted tubules in rats.MethodsThirty healthy adult SD rats in cleanliness grade were divided randomly into three groups:high and low dose arsen ism group with arsenism of 10.0 and 0.4 mg/kg·d,respectively,and control group with distilled water.Drinking water was contaminated with As2O3.The rats were exposed to the contaiminated drinking water freely for six months.The content of arsenic in the blood and urine of the rats was determined.The change of configuration and expression of caspase 3 in epithelium cells of proximal convoluted tubules of the kidneys of arsenism rats were observed with HE,strept vidin biotin complex(SABC)immunohistochem stry and image pattern analysis methods.ResultsCompared with the control group,a higher arsenic content in the blood and urine was found in both high and low dose arsenism group(P<0.01).Vacuole degeneration was found in epithelium cells and brush border of lumen surface fell o ff and reduced with pyknotic nucleus in proximal convoluted tubules of arsenism rats.The positive cells of caspase-3 was in creased in control group(1.30±1.02),low dose(16.00±8.23/a rea)and high dose(63.94±10.83/area)(P<0.05).While the grey scale was decreased sig nificantly in high dose(107.94±10.72/area)and low dose(148.23±11.74/a rea compared to that of the control group(P<0.05).ConclusionChronic arsenic poisoning may induce the expression of caspase-3 in epithelium cells in proximal convoluted tubules in rats.