Granuloma pouch assay. IV. Induction of sister-chromatid exchanges in vivo.

SCEs were induced, in vivo, in cells of a rapidly proliferating subcutaneous granulation tissue, initiated by the formation of a subcutaneous air pouch, on the backs of adult male rats (Granuloma Pouch Assay). 2 days after pouch formation the test compounds were applied, and 24 h later the granulation tissue was excised and dissociated into single cells. Isolated cells were cultured in vitro in media containing BrdU, and SCEs were determined within 24-48 h. The spontaneous frequency was 14.4 +/- 1.1 per metaphase. Mitomycin C (MMC) and cyclophosphamide (CP) induced a significant and dose-dependent increase in SCE frequencies. Results obtained after i.v., i.p. and intra-pouch application routes are compared.