Histopathological Changes of the Testes of Wistar Rats Following Metronidazole Administration

Damage to the human spermatozoa membrane due to oxidative stress caused by the toxic effects of metronidazole has been implicated as an important pathophysiological mechanism in male fertility. This study was designed to investigate the direct effects of metronidazole on the testicular tissue and that of the introduction of vitatmin E to metronidazole treated rats. It also looked at the natural reversal effects on abstinence from medication for 8weeks. A total of 105 adult male and 50 female wistar rats weighing 170±10g (70-90 day old) were used for the experiment. The rats were randomly divided into a control and experimental groups. There were four major groups with 5 subgroups consisting of 5 rats each. Varying doses of 15 mg/kg, 30 mg/kg, 200 mg/kg and 400 mg/kg of metronidazole were administered in experiment 1 to 4 respectively. Each experimental has 5 sub-groups: A; control, B; group administered with the experimental dose, C; experimental dose with vitamin E, D; experimental dose with testosterone, E; treated with experimental dose, vitamin E and testosterone. Sub-group F is a reversal group which was left for 8 weeks after cessation of treatment. At the end of the experiment, animals were scarified and testicular tissues were dissected out and weighed. Tissues were preserved in 50% Bouin fluid and thereafter prepared for histological studies. Results showed that metronidazole at the therapeutic dose of 15 mg/kg did not have significant negative effect on histology of the testis. At the dose of 30 mgkg, 200 mg/kg and 400 mg/kg some pathological changes were observed which were dose depended raging from mild interstitial edema, loss of germinal epithelium, foci of tubular wall thickening and widening of the interstitial spaces. Groups in which metronidazole was concurrently administered with vitamin E and or testosterone showed some levels of protection. The reversal groups showed normal to near normal histological features. The results of this study indicate that metronidazole administration (200 mg/kg or 400 mg/kg), for 8weeks, caused a harmful effect on the architecture of the testes and these effects were reversible after 8 weeks of abstinence.

Key Words: Metronidazole, histo-architecture, testis, vitamin E, testosterone