CHANGES IN SERTOLI AND GERM CELL NUMBER IN NEONATAL RATS

MORALES, A; SCIACCA, M.; CAVICCHIA, JC

MENDOZA, ARGENTINA

Congreso; XXVI REUNIÓN CIENTIFICA ANUAL SOCIEDAD DE BIOLOGÍA DE CUYO; 2008

SOCIEDAD DE BIOLOGÍA DE CUYO, ARGENTINA

Changes in Sertoli and germ cell number in neonatal rats.-An adequate critical relationship between Sertoli and germinal population sizes must be established during foetal and neonatal periods because it is necessary for a normal spermatogenesis. Sertoli cells show abundant proliferation around birth but they maintain a stable population after puberty. On the other side, germ cells are represented by gonocytes located in the center of the cords at birth, and then migrate to the periphery, settle on the basal membrane, and give rise to spermatogonia by mitosis. We studied cellular proliferation and apoptosis in both populations of testes of Wistar rats from birth to postnatal day 10. Testes were fixed and embedded in epoxi resin for light and electron microscopy. By light microscopy, cell counts were done in cross sections of seminiferous cords stained with toluidine blue. Since diameter of the cords change during the time of this study, results are expressed as indexes: mitotic or apoptotic figures per 100 total cells. During the first 7 days, the increase in the mitotic index is attributed to Sertoli cells, since gonocytes show few mitoses in the centre of the cord. However, from day 8 onwards, when gonocytes generate the first spermatogonia, smaller basal cells, it was difficult to differentiate their mitoses from Sertoli ones. Germ cell mitoses seem to predominate considering the numerous spermatogonia appearing in these days. About apoptosis index, there was a slight gradual increment but we couldn’t attribute it to either population at all with our methods. By transmission electron microscopy distinctive structures in mitotic and apoptotic figures were recognized to identify their cellular lineages.