Objective establishment a sub-chronic cadmium exposure model and detecting cadmium exposure can induce MSI in mice.Methods 50 mice (C57BL/6J) at 6 weeks of age were divided into 5 groups and intraperitoneal ly injected with 0, 0.25, 0.5, 1, or 2 mg/kg cadmium chloride quaque die alterna for 4 weeks.Then, the liver, kid ney, testis, leukocytes, bone marrow, and small intestine were collected from the treated mice.Portions of these tis sues were fixed for further histological analysis, and the remaining tissues were subjected to genomic DNA extraction for the analysis of a panel of 42 microsatellite markers.Results Severe histopathologic changes in the liver and kid neys, along with a complete disorganization of testicular structure and obvious severe necrosis in the testes, were ob served in the cadmium-treated group.After STR scanning, microsatellite instability (MSI) was found at 3 loci (D15Mit5, D10Mit266, and DxMit172) in the kidneys and leukocytes of mice in the lower dose groups (0.25, and 0.5 mg/kg).Conclusion we have successfully established a sub-chronic cadmium exposure model and confirmed that cadmium exposure can induce MSI in mice.We also identified two loci that could be regarded as "hotspots" of mic rosatellite mutation in mice.