Structural integrity of epididymal epithelial cells and ubiquitination process in epididymis of rats treated with H2 histamine receptor antagonist

Abstract

Cimetidine, an antagonist of H2 receptors, inhibits the acid chloride action and has been used for the treatment of intestinal and gastric ulcers. The treatment of patients with cimetidine has demonstrated to cause the following adverse effects: impotence, reduced sperm count, decreased libido and gynaecomastia. Studies have also demonstrated in rodents that cimetidine cause alterations in the testes, prostate, seminal vesicles and vas deferens. Some of these alterations have been related to a possible antiandrogenic effect of cimetidine. The sperm maturation in epididymis depends on the structural and functional integrity of epididymal epithelial cells. Among several epididymal functions, the clearance of damaged sperm by ubiquitin-proteaosome pathway has been demonstrated to be essential for the sperm quality. The aim of this study is to evaluate the effect of cimetidine on the structural integrity of the epididymal epthelial cells and on the process of ubiquitination in adult male rats. Ten male rats will be distributed into 10 groups: Control group (CG; n=5) and cimetidine group (CMTG; n=5). The animals from CMTG will receive daily intraperitoneal injections of cimetidine (100mg/kg) for 50 consecutive days and the animals from GC will receive saline. The epididymal cauda of each animal will be removed, fixed, dehydrated and embedded in historesin or parafin. Some fragments will be embedded in Araldite for analyses under the transmission electron microscope (TEM). Sections will be stained with H.E. for morphological and morphometrical analyses. The paraffin sections will be subjected to the immunofluorescence reaction for detection of ubiquitin - PGP 9.5 and cytocheratin 14 (basal cell marker). The epithelial high will be measured and results will be statistically analyzed. The ultrastructural analysis under TEM will be focused on the principal and clear cells to evaluate possible structural alterations caused by cimetidine in these cells.