Expression of BCL-2 family genes in germ cells undergoing apoptosis during the first wave of spermatogenesis in the rat.

Apoptosis is a key event controlling sperm output both in normal and pathological conditions. However, the mechanisms involving germ cell apoptosis is far from being understood. In this work, we have immunoisolated germ cells undergoing apoptosis by taking advantage of the up-regulation of Fas, a dead receptor involved in apoptosis induction in these cells. Analysis of specific markers showed that this cell population is composed of spermatogonia and meiotic spermatocytes. We measured the mRNA levels of several apoptosis-inducing proteins belonging to the BCL-2 family (BAX, BAD, PUMA, BOK and BAK) as well as those that prevent apoptosis (BCL-2, BCL-W and BCL-XL). Results showed that apoptotic germ cells have elevated mRNA levels of all studied genes (both pro and anti-apoptotic) compared with non-apoptotic cells. Our data would help to define the molecular mechanisms involving germ cell apoptosis under physiological conditions.