Environmental pollutants such as di-(2-ethylhexyl) phthalate (DEHP) adversely affect reproductive system tissue differentiation and functions with exposure at intrauterine, neonatal or adult stages of life, thereby potentiating male infertility later in life. World health organization estimates a global infertility prevalent rate of 10-15%, and 20-30% among Nigerians, with male factor constituting about 40-50% of infertility cases. This study was designed to investigate the effect(s) of oral vitamins C and E on DEHP induced changes in some semen parameters and serum testosterone concentration in adult Wistar rats. Seventy (70) adult male Wistar rats weighing between 156-250 g were randomised into 7 experimental groups 1, 2, 3, 4, 5, 6 and 7 (group n=10). Animals in groups 1, 2 and 3 were treated with 0.02 mg, 20 mg, 200 mg oral DEHP/kg bw daily respectively, while those in groups 4, 5 and 6, in addition to the above DEHP treatments, were treated with 100 mg ascorbic acid and 67.5 mg α-tocopherol per kg bw daily respectively. Rats in group 7 served as Control and were treated with vehicle. All treatments lasted for 60 days. After, over night fasting, samples of semen and serum were obtained for analysis. Results obtained were expressed as mean ± standard deviation and analyzed for significant differences in means using one way ANOVA and Post Hoc test. Relative to the control reference values, groups exposed to oral DEHP had significant (p<0.05) reduction in sperm count, total sperm motility, active sperm motility, normal sperm morphology, serum testosterone concentration and serum super oxide dismutase levels to 31.70±18.68x106 cells/mL, 38.60±24.78%, 8.50±5.66%, 38.00±18.00%, 9.56±1.34 ng/mL and 0.017±0.0013 units respectively. Sluggish sperm motility and abnormal sperm morphology significantly (p˂0.01) increased to 39.70±13.05% and 68.50±18.42% respectively. In the groups that had DEHP co-treatments with oral ascorbic acid and α-tocopherol, all studied parameters tended to comparative indifference statistically, with the Controls values. This indicates a protective function against DEHP effects on the studied parameters. The study has shown therefore, that DEHP inflicts oxidative stress in the reproductive system which potentially suppresses serum testosterone concentration with attendant derangements in the qualitative and quantitative sperm cells in adult Wistar rats, and thereby enhancing male infertility. However, the antioxidants ascorbic acid and α-tocopherol protects the gonadal and sperm cells from the harmful effects of DEHP by ameliorating oxidative stress and improving male fertility. This implies that there is need to avoid prolonged exposure to DEHP while encouraging the daily intake of oral ascorbic acid and α-tocopherol.
Effect of Oxidative Stress on Sperm Cells