Germ-cell mutagenicity of etoposide: induction of meiotic micronuclei in cultured rat seminiferous tubules.

Mutagen effects on male germ cells can be quantified by meiotic micronucleus induction in vitro. Late pachytene and diakinetic spermatocytes are able to differentiate through meiotic divisions in vitro and develop to round spermatids. In the presence of mutagens micronucleus induction reflects the potential of the chemical to induce chromosome breakage or uneven chromosome distribution. In this study we have investigated the mutagenicity of etoposide (VP-16) and its ability to induce micronuclei S-independently in meiosis by the meiotic micronucleus method in vitro. Our results indicate that etoposide is able to cause a statistically significant increase in the frequency of micronuclei at a concentration range as low as 0.5-8 mu mole/l. The meiotic micronucleus method in vitro seems to be a feasible and sensitive test system of male germ-cell mutagenesis.