A comparison of baseline and cyclophosphamide‐induced sister chromatid exchanges in bone marrow and spleen cells of mouse and chinese hamster

Abstract

Baseline sister chromatid exchange (SCE) frequencies were investigated in bone marrow and spleen cells of mice and Chinese hamsters. No significant difference in SCE frequency was noted for bone marrow in both species and for bone marrow and spleen in mice on per cell and per pg DNA basis. However, a significant difference was noted between species in spleen and between cell types in Chinese hamsters. Also, statistically significant differences were noted between species for both cell types when the same data were expressed on per chromosome basis. SCE levels in cultured bone marrow and spleen cells after intraperitoneal administration of the antineoplastic drug cyclophosphamide (10 and 20 mg/kg) differed significantly in mice and Chinese hamsters on per cell, per pg DNA content, and per chromosome basis. The spleen cells were much more sensitive to the effects of cyclophosphamide than bone marrow cells in both species. The replicative indices did not differ significantly between treated and control animals in either bone marrow or spleen cells of both species. Since SCE frequency is a sensitive measure of DNA damage, and bone marrow and lymphocytes are the most widely used cell types in human and animal in vivo assays, the methodologies and results reported here may be useful for comparative mammalian cytogenetic studies.