CONICET | Buscador de Institutos y Recursos Humanos

EFFICIENT LIPID PROCESSING AND EFFLUX FROM SERTOLI CELLS AFTER APOPTOTIC DEATH OF SPERMATOGENIC CELLS Ayuza Aresti PL , Oresti GM, Furland NE, Ferraris M and Aveldaño MI. INIBIBB, CONICET-UNS, 8000 Bahía Blanca, Argentina. Testicular exposure to X-rays and to temperatures higher than 38ºC compromise male fertility after some time because they induce germ cell apoptosis. The former mostly affects mitotically dividing spermatogonia and the latter mostly non-dividing spermatocytes and spermatids, both sparing Sertoli cells. In this study we surveyed the in vivo effects on rat testicular lipids and fatty acids several weeks after having locally irradiated (6.5 Gy) or heated (10 min, 43ºC) the testis. In both cases, Sertoli cells behaved as competent phagocytes that efficiently processed and disposed of materials formerly composing germ cells, including cholesterol and phospholipids. Germ-cell related 22:5n-6 of glycerophos-pholipids and very long chain polyunsaturated fatty acids (28:4n-6 and 30:5n-6) of spingomyelin and ceramide were eliminated from the testis. In the process, neutral glycerides and cholesterol esters (CE) temporarily increased, accumulating more 22:5n-6 than other fatty acids. The CE continued to build up for some weeks, reached a maximum, and eventually were also purged. The described changes including complete elimination of CE occurred earlier after hyperthermia than after irradiation, a slow but significant re-population of the testis with germ cells ensuing. The lipid results suggest that only when Sertoli cells have processed and got rid of all materials derived from germ cell corpses they are ready to resume support of a new round of spermatogenesis.