Age-related changes in the steroid-producing cells of rat testis

PURPOSE: Leydig cells are the main source of testicular hormones that control spermatogenesis, the male reproductive tract, and male secondary sexual characteristics. It is now well established that testosterone levels are reduced with ageing suggesting that there must be deficit in the steroidogenic capacity of ageing Leydig cells. In this respect, the present work aims at describing some structural and functional alterations in rat Leydig cells upon ageing.MATERIAL AND METHODS: Light and electron microscopic observations and immunohistochemistry for 3І-hydroxysteroid dehydrogenase (3І-HSD) were used to identify some structural and functional features of the Leydig cells of ageing rats.RESULTS: The routine histological analysis revealed that during aging (21 and 24 month- old rats) the Leydig cells undergo atrophic changes in size rather than reduction in their number and as consequence the interstitium of ageing testes appeared expanded. The immunoexpression of 3І-HSD as a marker of LC steroidogenic activity decreased after 18 months of age and the immunostaining considerably reduced in 24-month-old rats when compared to that in 3-month-old control ones. Ultrastructural study of Leydig cells in ageing rat testes revealed the presence of Leydig cells with intact morphology as well as Leydig cells with different degree of degeneration. An age-related progressive increase in the number of Leydig cells nuclei that exhibit apoptotic changes like chromatin fragmentation and compaction into dense masses leading to nuclear shrinkage was found out.CONCLUSION: The results obtained suggest that effects of ageing on steroidogenesis are mainly due to structural and functional alterations in Leydig cells resulting in a decreased testosterone production.Scripta Scientifica Medica 2013; 45(3): 32-35