Reproductive toxicological effects of gossypol on male rabbits: semen characteristics and hormonal levels

Abstract

Abstract The objective of this study was to evaluate the effects of two sublethal doses (4 and 20 mg/kg live weight (LW); every other day) of gossypol on semen and hormonal characteristics of male rabbits. The experiment lasted 16 weeks and included two periods: a treatment period (first 8 weeks) where the animals were given the test materials, and a recovery period (second 8 weeks) where drugs were withdrawn. Results showed that LW and respiration rate (RR) decreased ( P <0·05) among animals that received gossypol, while rectal temperature increased ( P <0·05). Animals in gossypol treatment groups had decreased ( P <0·05) blood plasma levels of tri-iodothyronine (T 3 ) and testosterone. This was accompanied by reductions ( P <0·05) in sperm concentration, total sperm output, percentage incidence of forward motility, total functional sperm fraction and semen initial fructose concentration. Gossypol however increased ( P <0·05) reaction time (i.e. decreased libido), percentages of dead sperm and abnormal sperm (AbSp) and altered acrosomes. Estimated weights of testes and semen ejaculate volume increased ( P <0·05) possibly due to increased water retention. Values of LW, RR, AbSp, and blood plasma T 3 and testosterone returned to control levels after withdrawal of gossypol, while the effect of this drug on other parameters continued during the recovery period.