Abstract

Methaq.A. Abd Alsamad, Mohammed A. Hasan, Yahya. O. Abdulhadi

The goal of the study was to elucidate the neurotoxicity of TOCP (Tri Ortho Cresyl Phosphate) in adult hen. forty adult hens were divided equally into two groups (treated and control) for acute study for 21 days as a single dose 2.5 mg / kg a day. Moreover, chronic study was done on eighty adult hens which divided into four groups (20 hens each); control group and treated groups which in turn supplemented with TOCP at 1.25, 2.5 and 5 mg/kg a day orally for ninety days and labeled as neurotoxicity induced groups. Most of transmission electron microscopic changes (TEMc) of cerebellum occurred in the synapses associated with degeneration of myelin sheath and/or partial demyelination in the presence of myelinated nerve fiber. Additionally, neurotoxicity of TOCP revealed abnormal lamellate of mitochondria with dark stained. The other adverse effects of TOCP extended into CNS (cerebellum and spinal cord) which was characterized by the degeneration of myelin sheath of myelinated nerve fibers with lamellated bodies’ formation, auto phagocytosis of degenerate myelin by oligo dendrocyte. Severe cases exhibited mitochondrial degeneration especially in the axoplasm of myelinated nerve fibers associated with calcification in the lamellated degenerated mitochondria with complete loss of neurons which lead to loss of function. These findings concluded that the histopathological results supported the clinical and biochemical findings, and the severity of nerve damage in a dose-dependent manner.