Critical Evaluation of the Role of Lycopene on Reproduction of Male Wistar Rats Exposed to Dimethoate

Aim: This study was aimed at evaluating the role of Lycopene on reproduction of male Wistar rats exposed to Dimethoate.

Experimental Design: A completely randomized experimental design using standard methods for analysis.

Location and Duration of Study: This study was carried out in the Animal house, Department of Animal and Environmental Biology of Rivers State University, Nkpolu-Oroworukwo Port Harcourt, Nigeria. GPS 4o47'50''N 6o58'49''E. This study lasted for 21days.

Methodology: Thirty male rats were randomly selected into five (5) groups A-E (6 animals per group). Groups B, C and D were gavaged 10, 20, 30 mg/kg/bw/day of dimethoate respectively, and co-administered Lycopene at 10mg/animal daily. Group E were administered 30mg/kg/bw/day of dimethoate without Lycopene. All animals were allowed access to cool clean water and standard rat pellet ad libitum. Twenty-four hours to the termination of the experiment, feed was withdrawn from the animals. Blood samples were collected by ocular puncture into heparinized tubes for hormonal analysis. Hormones such as Testosterone, Progesterone, estradiol, Follicle Stimulating Hormone (FSH) and luteinizing hormone (LH) were analysed based on the manufacturer’s instruction using Randox Monza assay kit. For Histopathological analysis of the testis, 0.5g of the testis was fixed in 10% formalin and sectioned with a digital Microtome (AO spencer No. 820) at 5μm thick. Histological sections were mounted on clean glass slides and stained with Hematoxylin and Eosin (H&E). The slides were viewed at X400 magnification (modified Orlu, 2014). Statistical analysis was carried out using one-way Analysis of Variance (ANOVA) and expressed as their respective units. Where significant differences were found, Pair-wise comparisons conducted with Tukey test using SPSS 22 software.

Results: It was observed that the level of all hormone considered decreased significantly with an increase in Dimethoate exposure despite the administration of lycopene. However, administration of dimethoate only resulted in a significant (p<0.05) reduction in the concentration of all hormones compared with groups given lycopene. The massive cellular degeneration observed in the seminiferous epithelium of experimental animals exposed to higher concentrations (20 and 30mg/kg/bw/day) of Dimethoate is indicative of a targeted action of the pesticide on male reproductive organ. The antioxidant property of Lycopene is clearly visible in testicular cross section of animals in groups given lycopene as gradual regeneration of both mitotic and meiotic spermatogenic elements were evidence.