Electron microscopic study of the left caput epididymal epithelium of adult albino rats in an experimental left varicocele model

ABSTRACT

Varicocele is a vascular lesion characterized by dilatation and tortuosity of the pampiniform plexus of the spermatic cord. It is one of the most common causes of male infertility. Most studies have focused on testicular function. Meanwhile, there are limited data in the literature on its impact on the epididymal structure. The aim of this study was to assess the effect of an experimental left varicocele on the histological structure of the left caput epididymis of adult albino rats and the cauda epididymal sperm count. Forty adult male albino rats [220-250 g] were randomly allocated to four equal groups. In group I [control group], rats did not undergo any surgical intervention. In group II [sham-operated group], animals underwent sham operation. The rats of groups III and IV underwent partial ligation of the left renal vein to create a varicocele and were sacrificed after 4 weeks and 8 weeks, respectively. Left caput epididymal strips of five rats of each group were harvested and prepared for light and electron microscopic examinations. Sperm samples were obtained from the left cauda epididymides of the remaining animals of each group for sperm count, and the results were statistically analyzed. There was a positive correlation between the sperm count and the duration of varicocele. Group III rats revealed a significantly lower sperm count as compared with the control and sham-operated groups. A significantly greater reduction in the sperm count was found in group IV rats as compared with group III rats. Histologically, varicocele-induced left caput epididymal alterations mainly involved the principal cells. They included cytoplasmic vacuolation and widening of the intercellular spaces in semithin sections of group III rats. Ultrastructurally, increased vesicular and vacuolar contents of the apical cytoplasm along with dilatation of Golgi saccules and rough endoplasmic reticulum were observed. The tubular lumina depicted several retained defective spermatids and spermatozoa with retained cytoplasmic droplets. With an increase in varicocele duration [in group IV], apparent thinning out of the lining epithelium with few stereocilia was observed in semithin sections. Ultrastructurally, the principal cells revealed a relatively dense cytoplasm and rather heterochromatic nuclei. The lumina were bordered with short, sparse microvilli and showed several defective spermatozoa. Experimental left varicocele induces evident histological alterations of the ipsilateral caput epididymis of adult rats and also a reduction in the caudal sperm count, both of which are duration dependent