Inducible protective processes in animal systems VI. Cross-adaptation and the influence of caffeine on the adaptive response in bone marrow cells of mouse

The effect of caffeine (CAF) (a replicative DNA synthesis inhibitor) given as pre-, inter- and post-treatments on the ethyl methanesulfonate (EMS)-induced adaptive response in in vivo mouse bone marrow cells was studied in order to understand the influence of CAF on the adaptive response. The pre-treatment was given 4 h before a combined treatment with EMS (conditioning + challenge) and in another set CAF was given as a conditioning dose and 4 h later the cells were challenged with a high dose of EMS. In the inter-treatment, CAF (40 mg/kg body wt) was administered 2 or 4 h after the conditioning dose of EMS and 6 or 4 h later the cells were challenged with a high dose of EMS. Similarly, in the post-treatment experiments, CAF was injected 6, 12 or 18 h after a combined treatment with EMS. The results revealed that the pre-, inter- and post-treatments with CAF significantly reduced the frequency of chromosomal aberrations compared with the challenge and combined treatments with EMS. It is interesting to note that CAF pre-treatment resulted in a much greater reduction in chromosomal aberrations compared with the inter- and post-treatments. Thus, this is an example of cross-adaptation induced by CAF in EMS-treated in vivo mouse bone marrow cells and the results also demonstrate an influence of CAF on the adaptive response.