Modulation of methotrexate-induced cytogenotoxicity in mouse spermatogonia and its transmission in the male germline by caffeine.

Apart from its own controversial cytogenotoxic effects, caffeine (CAF), one of the most commonly consumed alkaloids worldwide, is found potentiative to and so also protective from the cytogenotoxic effects of numerous chemical and physical mutagens. It also has modulated the actions of several antineoplastic agents. Additionally, it has been tested as a chemopreventive of cancer and is reportedly associated inversely with different cancer risks. Therefore, in the present study, three different sub-lethal doses of CAF, 25, 50 and 100mg/kg, were tested in mouse to assess their cytogenotoxic effects on dividing spermatogonia at 24h post-treatment, and transmission of such effects in the male germline from the primary spermatocytes and sperm at week 4 and week 8 post-treatment, respectively. CAF was found to be weakly clastogenic to mouse spermatogonia and the effects were also found transmitted in the male germline. Interestingly, such induced effects were quantitatively related to the dose of CAF tested. On the other hand, methotrexate (MTX), an antifolate antimetabolite, is prescribed frequently for the treatment of various types of cancers. However, MTX is reportedly clastogenic. Modulation of the said three different pre-treated doses of CAF on MTX 10mg/kg-induced cytogenotoxic effects, tested in the same experimental protocol, indicated that CAF pre-treatment was decreasing the MTX-induced clastogenicity in spermatogonia, and was lowering the concurrent transmission of such effects in the male germline of mice, significantly. Such decreases were related to the dose of CAF tested, i.e. higher the dose of CAF more was the decrease in the MTX-induced cytogenotoxic effects and in their transmission. The possible mechanisms that might have caused the manifestation of a weak clastogenic action of CAF on spermatogonia and in its transmission in the male germline, and the CAF modulation of MTX-induced cytogenotoxic effects in spermatogonia and in their transmission have been discussed.