Histological Insights into Testicular Apoptosis Associated with Spermatogenesis in Pre-Pubertal and Adult Meagre (Argyrosomus regius)

To overcome reproductive dysfunctions, recombinant gonadotropin hormones have been synthesised in different fish species. We were interested in gaining further insight into the effects of recombinant follicle-stimulating hormone (rFsh) in meagre Argyrosomus regius spermatogenesis and in improving the existing knowledge on the role of testicular apoptosis. Germ cell composition and testicular apoptosis were compared in pre-pubertal fish treated with rFsh (PreP-Fsh) and controls (PreP-C), and adult meagre with testes in the proliferative (Adult-Pro) and meiotic (Adult-Meio) spermatogenesis phases. A lower density of committed spermatogonia was observed in PreP-Fsh compared with PreP-C and in Adult-Meio compared with Adult-Pro. In pre-pubertal fish and in Adult-Pro, apoptosis affected mainly individual germ cells and Sertoli cells. In Adult-Meio, a high number of cysts containing apoptotic germ cells was observed, and apoptosis often involved entire clones of germ cells. rFsh reduced testicular apoptosis in pre-pubertal fish, whereas the advancement of spermatogenesis in adults was associated with an increased density of apoptotic cells. The present study corroborated previous observations on the effects of rFsh on spermatogenesis in pre-pubertal meagre and provided further insights on the changing role of apoptosis in the pre-pubertal phase versus different phases of spermatogenesis.