Effects of Ethanolic Extract of Dioscorea villosa Tubers on Male Reproductive Parameters in Wistar Rats

Aim: The current study investigates the effect of the ethanoic extract of Dioscorea villosa on male reproductive parameters using wistar rats.

Study Design: Twenty four male rats were randomly sorted into 6 groups (4 rats/group). Group 1 served as the short term control group and Group 2 served as the long term control group. Both groups were given water and rat chow ad libitum with no dose of the extract. Group 3 served as the short term low dose group and Group 4 as the long term low dose group. Both groups were administered 100 mg/kg body weight of Dioscorea villosa extract for 14 days and 28 days respectively using distilled water as the medium. Group 6 served as the short term high dose group and group 5 as the long term high dose group. Both groups were administered 400 mg/kg body weight of the Dioscorea villosa extract for 14 days and 28 days respectively, using distilled water as the medium.

Methodology: After the last day of administration (the 15th for the short term groups and the 29th day for the long term groups), the animals were sacrificed by cervical dislocation, fasting serum samples were obtained for the sex hormone analysis, cauda epididymis were dissected for sperm count, motility and viability, and organ weights of the testis and seminal vesicle were taken. Histopathological changes of the testis were also studied.

Results: Dioscorea villosa extract caused significant changes in the sperm count, serum FSH, LH and Testosterone levels of the short term groups and a significant change in the serum Testosterone level of the long term group. There was an increase in the sperm count in the short term groups when compared to the short term control group with that of the high dose being statistically greater than the low dose group. The serum levels of follicle stimulating hormones (FSH), luteinising hormones (LH) and Testosterone decreased in the low dose group but were all increased in the high dose group when compared to the short term control. The long term group recorded an increase in the serum testosterone level in the high dose group when compared with the long term control group. There however was no significant improvement in the sperm motility and viability of the groups given low and high dose of extract when compared to that of the control group. There was no any statistically significant changes in the weight differences of the rats between the experimental and control groups. The control group showed a decrease in weight of -8.30±6.86% while the low dose (100 mg/kg bwt) and high dose (400 mg/kg bwt) groups showed differences of -6.80±3.25% and 1.44±1.73% respectively. There was also no significant weight loss or weight gain of the reproductive organs (testis and seminal vesicles) was noticed, in both the short term low dose (100 mg/kg bwt) and high dose (400 mg/kg bwt) groups when compared to that of the control group.

Conclusion: The result suggests that Dioscorea villosa has significant effects on male reproductive parameters both in short term and long term administration. It also showed significant effect both in low and high doses.