The Effect of Chronic Use of Dextromethorphan on Fertility in Male Sprague-Dawley Rats: A Pilot Study

Abstract

Background: The abuse of cough syrups containing dextromethorphan is increasingly becoming popular among young people. Objective: This pilot study was designed to investigate the effect of dextromethorphan (DM) on fecundity and to evaluate the reversibility of its reported deleterious effect on the testes upon discontinuation. Method: Forty-eight (48) male Sprague-Dawley rats were used and divided into 8 groups (n = 6) as follows: Group 1 = distilled water control (10 ml/kg, p.o.), Groups 2-4: 20, 40 or 80 mg/kg; p.o., respectively for 4 weeks; Group 5: distilled water control (10 ml/ kg, p.o.), Groups 6-8: 20, 40 or 80 mg/kg, p.o.; respectively for 8 weeks. At the end of the treatments, 3 rats were randomly selected from each group and mated with females of proven fertility on late proestrous phase identified by vaginal cytology. The male rats were sacrificed by cervical dislocation immediately the presence of spermatocytes was confirmed in the vaginal smear the next morning on estrus. Semen parameters were analysed and the testes were weighted and fixed in Bouin’s fluid. The remaining 3 rats from each group were used to assess recovery rate after 2 and 4 weeks respectively; they were mated and the above parameters were assayed. Results: Significant decrease in testicular weight was observed and this was highest at the 80 mg/kg dose in both the 4 and 8 weeks treatment groups and recovery groups compared to control. Generally, sperm count, sperm motility and percentage normal morphology reduced significantly in the treatment and recovery groups compared to the control groups in both the 4 and 8 weeks studies. Of these 3 parameters studied, sperm count recorded highest reduction compared to control in both the treatment and recovery groups. Histological sections of the testes from 40 and 80 mg/kg groups showed moderate to severe atrophy of seminiferous tubules and spermatozoa were sparsely present in the lumen. Also, no pups were littered to female rats in the 40 and 80 mg/kg groups in both the treatment and recovery studies. Conclusion: Results showed that chronic use of DM produces deleterious effect on the histoarchitecture of the testes and reduces semen parameters leading to infertility in males (infecundity) which was not reversed upon withdrawal.