Toxic Effects of Lead Exposure on Hypothalamo–Pituitary–Ovarian Axis in Striped Dwarf Catfish, Mystus vittatus (Bloch, 1794)

Present study aimed to explore the adverse effects of lead (Pb) induced reactive oxygen species (ROS) generation on hypothalamo–pituitary–ovarian axis. Adult female Mystus vittatus (n = 48) were exposed to lead nitrate at 0.0 mg/L (control) and 6.02 mg/L (safe dose; 1/10th of LC50 dose) for 60 days. Fish were sacrificed at 15 days interval to collect brain, ovary and serum. Lead concentration in fish tissues increased significantly (p < 0.05) with exposure duration. ROS generation in brain and ovary increased significantly (p < 0.05) in Pb-induced group compared to control. Increased level of lipid peroxidation due to lead induced oxidative stress was marked by significant increase (p < 0.05) in malondialdehyde level in fish brain and ovary compared to control. Significant increase (p < 0.05) were found in reduced glutathione, super oxide dismutase, catalase, glutathione s-transferase, glutathione reductase level in fish brain and ovary in Pb-induced group with exposure duration. Glutathione peroxidase level decreased significantly (p < 0.05) after 30 days of exposure. Brain gonadotropin-releasing hormone and kisspeptin level decreased significantly (p < 0.05) and gonadotropin-inhibitory hormone level increased significantly (p < 0.05) in lead exposed fish. Serum follicle stimulating hormone, luteinizing hormone and ovarian vitellogenin, estradiol, maturation inducing hormone level decreased significantly (p < 0.05) with metal exposure. An increased metallothionein level was found in both brain and ovary of metal exposed fish. Current study illuminated the effect of Pb-induced oxidative stress and its consequences on the reproductive endocrine pathway in female M. vittatus.