Testis histology and plasma testosterone levels in the Mongolian gerbil (Meriones unguiculatus) after vasectomy

The Mongolian gerbil (Meriones unguiculatus) is a small rodent widely used in laboratory for biomedical and behavioural research. When the experimental protocol requires male contraception, vasectomy is one of the methods most used, although its effects on spermatogenesis in the Mongolian gerbil had never been investigated. In the present study, fertile male Mongolian gerbils were vasectomized for a histological survey of the testis and measurement of plasma testosterone levels. The main effects of vasectomy were: vacuolization and marked reduction of the germinal epithelium, increase in heterochromatin in some Sertoli cell nuclei, thickening of the tunica albuginea, widening of the interstitial space, appearance of macrophagic giant cells, and degeneration of the epithelium of the tubuli rectae. However, neither morphological changes in the Leydig cells nor alteration in the plasma testosterone levels were found. In conclusion, these preliminary results indicate that vasectomy, at least over a short time span, can impair spermatogenesis without affecting the production of plasma testosterone.