Protective role of isoflavones against the toxic effect of cypermethrin on semen quality and testosterone levels of rabbits.

Cypermethrin is considered as one of the endocrine disruptors. Isoflavones play an important role in various physiological processes in the body. It has both estrogenic and antioxidant effects. The objective of this study was to evaluate the protective role of isoflavones (2 mg/kg B.W) on semen quality and plasma testosterone levels of male New Zealand White rabbits given sublethal dose (24 mg/kg BW every other day for 12 weeks) of cypermethrin. Results showed that treatment with cypermethrin caused a significant decreases (P < 0.05) in ejaculate volume, sperm concentration, total sperm output, sperm motility (%), total motile sperm per ejaculate (TMS), packed sperm volume (PSV), semen initial fructose and plasma testosterone. In addition, live body weight (LBW), dry matter intake (DMI) and relative weights of testes and epididymis were decreased. On the other hand, treatment with cypermethrin increased (P < 0.05) the numbers of abnormal and dead sperms, and initial hydrogen ion concentration (pH). Results indicated that the presence of isoflavones together with cypermethrin was capable to minimize its harmful effects. Treatment with isoflavones alone had positive effects on some semen characteristics in spite of it is considered as estrogen-like compound. Since it causes significant increases in libido (by decreasing the reaction time), PSV, sperm motility and TMS, while abnormal and dead sperm were reduced compared to control animals. Meanwhile, isoflavones had no negative effect on ejaculate volume, total sperm output, sperm concentration, initial fructose concentration, pH and plasma testosterone levels. Results demonstrated the beneficial influences of isoflavones in reducing the negative effects of cypermethrin on reproductive characteristics of mature male rabbits. Interestingly, data showed that isoflavones alone caused an improvement in some semen quality and had no negative effects on male fertility, and did not have negative effects on male fertility.