Phoxim Induced Neurotoxicity of Diencephalon and Medulla Oblongata via Induction of Oxidative Stress and Apoptosis

Phoxim is a widely used orgnophosphorus pesticide, particularly in veterinary and agricultural fields. Its excessive use exhibits toxic effect andinduces tissue damage. In the current study, the histopathological and biochemical changes of different brain regions including thalamus, hypothalamus and medulla oblongata have been evaluated after phoxim exposure.We also examined the ability of phoxim to induce oxidative stress and subsequently apoptosisin these regions. Twenty Wistar adult male albino rats were used in our study, and they were split into two groups of ten rats each. Over the course of 30 days, the phoxim-exposed group received 100 mg/kg body weight daily by oral gavage, while the control group received 1 ml of soybean oil daily. Then tissue samples from all groups were collected for histopathological, immunohistochemical and biochemical examination. Phoxim treated group revealed alteration of the histoarchitecture of the examined brain regions in the form of neuronal degeneration, neuropilvacuolation and glia cells infiltration. Moreover, immunohistochemical findings exhibited strong positive expression of cytochrome c and cleaved caspase-3 andmild immunoreactivity to Nrf-2 after phoxim exposure. Furthermore, phoxim was able to decreaseGSH and significantly increaseMDA, upregulateTNF-α and downregulate BDNF. We can conclude that phoxim causes oxidative stress and subsequently induces apoptosis and neurotoxicity of different brain regions.