EVALUATION OF TESTICULAR LESIONS AND SERUM HORMONE LEVELS IN RATS EXPOSED TO LEACHATE FROM MUNICIPAL BATTERY RECYCLING SITE

Abstract

Increased infertility rate among men arising from the incidence and prevalence of testicular lesions has been linked to exposure to several toxicants in the environment. Therefore, this study was undertaken to investigate the reproductive functions in rats exposed to different doses of leachate obtained from Elewi Odo municipal battery recycling site, Ibadan Oyo State, Nigeria. The leachate was prepared and heavy metal contents [Copper (Cu), Lead (Pb), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Iron (Fe), Manganese (Mn), Nickel (Ni) and Zinc (Zn)] were determined using atomic absorption spectrophotometer (AAS). Subsequently, the ability of the leachate to induce hydroxyl (OH•) radical production and lipid peroxidation were determined in vitro. Then, acute toxicity of the leachate (lipid peroxidation and hepatic enzymes) was determined following short-term exposure of rats to the leachate. Thereafter, some key markers linked with spermatogenesis and fertility were determined after long-term exposure to the leachate (60 days). The heavy metal content of the leachate [Cd (0.006 mg/L), Cr (0.068 mg/ L), Fe (2.667 mg/L), Ni (0.05 mg/L), Pb (0.015 mg/L) and Mn (7.842 mg/L)] were higher than the permissible limits [Cd (0.003 mg/L), Cr (0.05 mg/L), Fe (0.30 mg/L), Ni (0.02 mg/L), Pb (0.01 mg/L) and Mn (0.40 mg/L)] set by World Health Organisation (WHO). The leachate induced the production of hydroxyl (OH•) radical and lipid peroxidation in vitro. Short-term exposure (7 days) of rats revealed that the leachate significantly (P<0.05) increased the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), ϓ-glutammyl-transferase (GGT) in the plasma and testicular malonaldehyde (MDA) level. Furthermore, long-term exposure of rats to the leachate significantly (P<0.05) reduced the key markers linked with spermatogenesis and fertility [3 β- hydroxyl steroid dehydrogenase (3β-HSD), 17 β-hydroxyl steroid dehydrogenase (17- βHSD), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, sperm count, sperm motility and daily sperm production (DSP)]. Therefore, exposure to leachate from municipal auto-battery recycling site could cause infertility in rat.