Effect of aging and hormonal replacement therapy on rat testes: Links with apoptosis, mitochondrial function and oxidative stress

This study was designed to investigate the mechanisms underlying age related decline in spermatogenesis. Four groups (Gp) of rats of 6,12,16&26 mo old were included. GpIII was subdivided into a,b & c. s.c. testosterone (T) and oral vit E were given for Gp III a & b,respectively. PlasmaT, bioactiveT, LH and FSH were measured. Apoptosis of the testes was detected by TUNEL and E.M. Testicular telomerase activity, GSSG/GSH, cytochrome c oxidase & 8-OHdG were estimated. The results showed rat aging began at 16 mo old & manifested by decrease in bioactive T, free T and LH, whereas FSH increased. Apoptotic index increase & mitochondrial changes of Leydig cells started at 16 mo. The concomitant decrease of mitochondrial CCO & increase in GSSG/GSH support the mitochondrial role in age related germ cell loss via apoptosis. The slight improvement of these parameters in groups IIIa&b indicate that endocrine aging in males is inevitable.