Testicular morphology and epididymal sperm reserves of male rats following the withdrawal of Nigerian Qua Iboe Brent crude oil

The reversibility of crude oil-induced male reproductive abnormalities was studied in fifty-six male Sprague-Dawley rats. Exposure to crude oil was achieved by oral administration of increasing doses (165mg/kg body mass, 330mg/kg body mass, and 660mg/kg body mass) of Nigerian Qua Iboe Brent crude oil to male rats every 48 hours for 4 weeks. Thereafter, the crude oil was withdrawn from some of the rats for a period of 8 weeks. The results showed significant reduction in the cauda epididymal sperm reserves of the rats that received the crude oil (P<0.05) and the rats from which the crude oil was withdrawn (P<0.05), relative to the control group. The testes of the rats that received crude oil showed reduced spermatogenic activity in the seminiferous tubules, as well as hyperaemia and oedema of the interstices. The testes of the rats from which crude oil was withdrawn showed evidence of recovery and the restoration of active spermatogenesis in the seminiferous tubules. The indication is that the withdrawal of Nigerian Qua Iboc Brent crude oil from male rats over a period of 8 weeks reversed the testicular pathology, but not the cauda epididymal oligospermia associated with this environmental pollutant.