Protective effects of green tea (Camellia sinensis) extract against cypermethrin-induced neurotoxicity in rainbow trout (Oncorhynchus mykiss) brain tissues

This study was conducted to evaluate the protective impacts of green tea extract (GT) against cypermethrin-induced (CYP) neurotoxicity parameters such as acetylcholinesterase activity, oxidative stress, immune response, histopathology, apoptosis, and DNA damage in the brain tissues of rainbow trout (Oncorhynchus mykiss). The trial was divided into four groups (group 1, 2, 3 and 4). Group 1 was the control, while group 2 was treated with 0.1 mg/l of CYP, group 3 was treated with 0.1 mg/l of CYP + 100 mg/l of GT and group 4 was treated with 0.1 mg/l of CYP + 200 mg/l of GT for 14 days. While the level of malondialdehyde increased, the exposure to CYP in group 2 resulted in a reduction in acetylcholinesterase, lysozyme, total immunoglobulin, white blood cell, superoxide dismutase, and catalase levels in the brain tissues, as compared to group 1. Furthermore, CYP exposure in group 2 resulted in severe hyperaemia in meningeal and parenchymal vessels, accompanied by significant degeneration and necrosis. In addition, neurons in group 2 exhibited pronounced cytoplasmic expressions of 8-OHdG and caspase-3. On the contrary, both doses of 100 mg/l and 200 mg/l of GT demonstrated remarkable neuroprotective impacts against CYP toxicity across all parameters as mentioned above. In summary, this study conclusively showed that the administration of 200 mg dose of GT yielded more pronounced neuroprotective impacts, surpassing the impacts observed with the 100 mg dose of GT. The higher dosage effectively reduced CYP-induced oxidative stress, apoptosis and DNA damage, while exhibiting an enhanced immune response.