Surgical Induction of Varicocele in the Rabbit

Abstract

Surgically induced varicoceles were created in male rabbits of proven fertility by partially occluding the left lumbotesticular trunk, which receives the left testicular vein before draining into the left renal vein. Semen was collected every 2 weeks following surgery and left testicular biopsy was performed at 2, 4, 8 and 13 postoperative weeks. Tissue was processed for light and electron microscopy. Animals were sacrificed at 20 postoperative weeks. Left testicular vein dilatation was observed at autopsy (20 weeks postoperative), as were changes in semen quality. These included an increase in the number of round germ cells and abnormal spermatozoa, as well as a decrease in sperm numeric density and motility. Seminiferous tubule pathology was variable and germ cell sloughing was observed as soon as 8 weeks following surgery. Spermatids were maloriented relative to Sertoli cells and Sertoli-germ cell junctional complexes were structurally abnormal. Results indicate that surgical induction of varicocele in the rabbit leads to altered spermatogenic function and decreased semen quality similar to that described in humans. Epithelial disruption appears to be a phenomenon of the adluminal testicular compartment and apical Sertoli cell cytoplasmic degeneration may account for the poor semen quality associated with varicocele.

The effects of experimental varicocele on testicular histology and fertility in monorchic adult rats

“…In the present study, the incidence of histological abnormalities caused by experimental varicocele in the left testes of right orchidectomized rats was higher than that in intact rats, but the differences were not statistically significant. Although experimental left varicocele in adult rats has been reported to cause no changes in testicular weights, the experimental varicocele in adult rats reduced ipsilateral testicular weights significantly [ 9–12]. This contradiction may be attributed to the longer duration of varicocele in the present study (≈3 months).…”

Effects of Morinda officinalis Polysaccharide on Experimental Varicocele Rats

“…To date, three classes of TJ transmembrane proteins and one of associated proteins (linking transmembrane proteins to the cytoskeleton) have been confirmed in the testis, including Occludin, Claudin, junctional adhesion molecules (JAM), and zonula occludens (ZO) [45, 46]. TJ proteins in Sertoli cells are more sensitive to reproductive toxicity, possibly due to the unique dynamics of TJ [23, 28, 29]. Meanwhile, destruction of junctional complex between Sertoli cells or Sertoli and germ cells may result in spermatogenesis obstruction [47].…”

“…So far, there are several conceivable mechanisms involved in the pathophysiology of varicocele, including the higher temperature of testis induced by poor venous drainage, the disorder of neuroendocrine system, the hypoxia of testis, the accumulation of metabolites in testis, the regurgitation of adrenal and renal metabolites, and the high levels of oxidative stress in left testis [25–27]. The Sertoli cell in varicocele is reported to be more sensitive than germ cells to changes in the testicular microenvironment [28] and the structure of the TJ between Sertoli cells is damaged in experimental varicocele in the rat testis [29, 30], implying that the Sertoli cell may be the primary altered intratubular site, leading to secondary spermatogenesis obstruction. In addition, the circulating antisperm antibodies can be detected in men with varicoceles, which imply that the structure of TJ (the primary composition of BTB) is disrupted probably [31].…”

Molecular and other predictors for infertility in patients with varicoceles

“…Partial constriction of the left testicular vein of animals produces more uniform varicocele effects than found in man (26,255). Varicocele models have been created in rat (256,257); dog (38); rabbit (258,259) and monkey (260)(261)(262). In the models that achieved visible evidence of venous distension, there was a reproducible increase in bilateral blood flow, intratesticular temperature and interstitial pressures in all species.…”