Germ Cells Apoptosis during Spermatogenesis in Mammals
Sharma RK, Bhat RA, Goyal AK, Bhardwaj JK
Cellular apoptosis is one of the prominent processes observed in testicular development and normal spermatogenesis. This is essential because mammalian spermatogenesis is a complex process that requires precise homeostasis of different cell types. Sertoli cells, which tightly regulate germ cell proliferation and differentiation, are implicated in the control of germ cell apoptosis. A lot of information is available on different cellular (morphological including ultra-structure), molecular, endocrine, biochemical and genetic regulation of germ cell apoptosis in testis that has inspired researchers and biologists to explore greater details in the intricacies of this finely tuned phenomenon. Various endocrine, exocrine factors, toxins, drugs, metabolites and peptides triggering the cascade of events leading to activation of specific genes and their up and down interplay has been discussed in detail. The important aspect of this review is that detailed morphology of testicular tissue and apoptotic cells has been analyzed by light as well as by electron microscopy. The significance of apoptosis in germ cell differentiation and screening vis-à-vis various selection criterions have been analyzed to specify the positive and negative selective pressures (environmental, nutritional) towards evolving reproductive success.