Quantitative (stereological) study of the effects of vasectomy on spermatogenesis in rabbits

Abstract

Using stereological methods, especially the optical disector for unbiased estimation of nuclear number, our recent study demonstrated that long-term (6 or 12 months) vasectomy in the rhesus monkey had no significant effects on spermatogenesis (Peng et al. Reproduction 2002, 124, 847-856). This study aimed to determine the scenario in the rabbit using the same morphometric methodology. Three groups of normal male Japanese white rabbits (aged 4-5 months) were subjected to unilateral vasectomy; 10 days, 6 months and 12 months later both testes and epididymides were removed. Testicular and epididymal methacrylate-embedded sections were obtained for stereology.Vasectomy-induced damage to spermatogenesis was observed, primarily sloughing of spermatogenic cells with a greater reduction in the number of advanced (adluminal) cells. The damage was most severe at 10 days, occurring in all the testes on the vasectomized side and involving sloughing of even type A spermatogonia, the number of which returned to normal at 6 and 12 months. Damage was less severe at 6 and 12 months, being found in half of the testes of the vasectomy side, in which the total numbers of later germ cell types were 24.0-59.1% (spermatocytes) and 0.3-11.6% (spermatids) of control at 6 months, and 20.1-22.1% (spermatocytes) and 0.4-12.0% (spermatids) of control at 12 months. By contrast, Sertoli cell number per testis was unchanged following vasectomy in any group.Epididymis on the vasectomy side, especially at 10 days and 6 months, appeared larger than on the contralateral side, but this difference was not statistically significant, and no sperm granuloma was seen in the epididymis.

Effect of vasectomy via inguinal canal on spermatogenesis in rabbits

“…An earlier study also observed spermatogenic damage 3-28 months after vasectomy in rabbits [9]. The damage was likely related to the increase of intra-testicular pressure induced by the vasal blockage of sperm transportation [8,10]. We specu-.…”

“…Our previous studies in rabbits showed that vasectomy (via the scrotum) resulted in severe spermatogenic damage, which was evident 10 days, 3, 6 or 12 months after operation [7,8]. An earlier study also observed spermatogenic damage 3-28 months after vasectomy in rabbits [9].…”

The effect of unilateral vasectomy on testosterone and testicular parameters in the adult male African giant rat (<i>Cricetomys gambianus</i>)

“…Antypas et al 1 showed that a bilateral deficiency in both Leydig and Sertoli cell secretory functions occurs in unilaterally vasectomized animals with an overall result of bilaterally impaired spermatogenesis and inhibited sperm maturation process. Previous studies by Saifzadeh and Derakhshanfar 12 and Kong et al 13 utilized 12 native Sprague-Dawley rats and 19 Japanese rabbits in their investigations on unilateral vasectomy. Our present study focuses on the effects of unilateral vasectomy on testicular histology, testosterone and seminal parameters in the AGR.…”

The Effects of Vasectomy on Epididymal Morphology and Sperm Parameters in Adult Male Balb/c mice

“…Gatti et al, reported that sperm forward motility is the result of a balance between maturation of the flagellum and prevention of the flagellar machinery that keeps spermatozoa in an immotile state. In a study conducted on rabbits, Kong et al (2004), found out that vasectomy causes severe spermatogenic damage, which is evident 10 days, 3, 6 or 12 months after operation.…”