Abstract: Objective: The aim of this study is to explore the sub-chronic toxicity of sodium selenite. Methods: Wistar rats were randomly divided into three groups and administered with sodium selenite at the doses of 0.470, 0.235 mg/kg and 0.118 mg/kg (1/25－1/100 LD50) for 12 consecutive weeks. Each rat was subjected to recovery observation for another 2 weeks after stopping administration of sodium selenite. The blood and major organs were harvested at the end of 12th and 14th week to investigate the effect of sodium selenite on the growth, histopathological change, blood routine index and blood biochemical index of rats. Results: Sodium selentie at the dose of 0.235 mg/kg revealed an obvious inhibitory effect on the growth of rats. Meanwhile, it also exhibited different influences on major organs, blood routine indexes and blood biochemical indexes. Histopathological examination indicated that the major organs including heart, liver, spleen, lung, kidney and intestine were damaged. Conclusion: Sodium selenite has sub-chronic toxicity to rats. The lowest adverse effect level of sodium selenite can be observed at the level of 0.235 mg/kg, and no adverse effect level of sodium selenite occurs at the level of 0.118 mg/kg. The damage to rats can result in partly reversible effect without any delayed toxicity in a short term.

Key words: sodium selenite, sub-chronic toxicity, rat