Localization pattern of visfatin (NAMPT) in d-galactose induced aged rat testis

Aging is a complex irreversible process which leads to decline in body physiology including reproductive activity. Neurological and brain functions defects have been studied in the d-gal induced aging rodent model. However, there is dearth of literature on reproductive aging induced by d-gal treatment. Visfatin is an adipokine which regulates testicular steroidogenesis and its level increases under stress conditions to cope and extend longevity. To the best of our knowledge the expression and localization pattern of visfatin and histological evaluation of d-gal induced aged testis have not been investigated. Thus, we hypothesized that the expression pattern and histoarchitecture of d-gal induced aged testis are impaired. Therefore, the aim of the present study was to elucidate the histopthological, immunohistochemical localization and expression of visfatin in d-gal induced aged testis along with serum testosterone level, sperm count and daily sperm production. The western blot and immunohistochemical results of the present study showed that d-gal treatment decreases visfatin expression in the testis, particularly in the Leydig cell, and decreases serum testosterone level. Further, d-gal treatment decrease in testosterone levels was positively correlated with decreases in Johnsen's score, mean seminiferous tubule diameter, germinal epithelium height, sperm count and daily sperm production. The multinucleated giant cells showed strong immunostaining for visfatin and suggest the role of visfatin as pro/anti-apoptotic factor. Thus, it can be suggested that visfatin may play an important role in testicular aging by regulating testicular steroidogenesis and spermatogenesis.