The effect of crude extract of the bark of Carica papaya on the seminiferous tubules of male Sprague-Dawley rats.

The contraceptive potential of an aqueous crude extract of the bark of Carica papaya administered orally is reported at the dose regime of 5 and 10 ml/animal/day for 4 weeks. Although the body weight or the weights of reproductive organs, kidneys, adrenals remained unaltered during the course of treatment, there was significant alteration in the histology of the testis and semen analysis when compared to the intact control group. The seminiferous tubules of rats treated with low doses of Carica papaya for 4 weeks showed no significant histological changes compared with the control. At the high dose concentration of the extract there was disorganisation in some of the seminiferous tubules with arrest of spermatogenesis beyond the level of spermatocytes. There was also widening of the lumen of the tubules. Seminal analysis showed some of the motile spermatozoa with abnormal feature in all the experimental groups. There was a dose-dependent suppression of sperm progressive forward motility which coincided with a decrease in sperm count, viability and a dose-dependent increase in percentage abnormal spermatozoa during the 14-28 days experimental period. Taken together, the present experiment showed that complete loss of fertility is attributed to decline in sperm motility and alteration in their morphology and suggest that the aqueous extracts of Carica papaya bark is safe and could serve as an effective male contraceptive in animals.