-Chlorpyrifos (CPF) is one of the most widely used organophosphorous insecticides in agriculture with its attendant adverse health outcomes. This study aimed at evaluating the effect of subchronic oral CPF administration on hematological and serum biochemical indices, and the possible ameliorating effect of vitamin C on the indices in mice. Thirty mice divided into 3 groups of 10 mice each were used for this study. Mice in group I (control) were dosed with vegetable oil, while those in group II were given CPF (21.3 mg/kg~ 1/5 th LD 50 ) only. Mice in group III were pretreated with vitamin C (100 mg/kg) prior to dosing with CPF 30 min later (Vitamin C + CPF-treated group). This regime was given to each group of mice three times a week for a period of ten weeks. During the study period, mice were examined for signs of toxicity, and weight of each mouse was measured every week. At the end of the study period, blood samples were collected from the mice and analyzed for packed cell volume (PCV), total red blood cell (RBC), white blood cell (WBC) and total protein (TP). Serum obtained from the blood was analyzed for Na + , K + and Cl − , urea, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). The results showed that mice in the vitamin C + CPF-treated group exhibited milder signs of toxicity and significant increase in weight gain (p<0.01) compared to the CPF-treated group. No significant increase in weight in the CPF-treated group was observed compared to the control. There was a significant increase in PCV, RBC, Hb, TP and creatinine, but a significant decrease was obtained in WBC, ALT and AST in the CPF-treated group compared to the control. All the parameters with the exception of WBC, ALT and AST (which increased significantly), were significantly decreased in the vitamin C + CPF-treated group compared to CPF-treated group. ALP was significantly elevated in the CPF-treated group compared to both the control and vitamin C + CPF-treated group. No significant changes in urea and the measured electrolytes in all three groups, except a significant decrease in the concentration of Na + was observed in the CPF-treated group compared to the control. The study demonstrated that pretreatment of CPF-administered mice with vitamin C significantly altered some important hematological and serum biochemical parameters, revealing the protective action of the vitamin against some organ damage induced by CPF.

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Chronic exposure to chlorpyrifos (CPF) has been shown to cause increased lipoperoxidative changes in the erythrocyte membranes. The relationship between chronic CPF-induced lipoperoxidative changes and erythrocyte fragility has not been elucidated. The aim of the present study is to evaluate the role of lipoperoxidation on CPF-induced erythrocyte fragility and the ameliorative effect of vitamin C. Twenty animals divided at random into four groups of five animals each served as subject for this study. Rats in group I served as the control group and were given only soya oil at a dose of 2 mL/kg body weight (b.w.). Rats in group II were dosed with vitamin C (100 mg/kg b.w.) and then supplemented with soya oil (2 mL/kg b.w.), while those in group III were administered with CPF only at a dose of 10.6 mg/kg b.w. (∼one-eighth of the previously determined median lethal dose [LD50]). Rats in group IV were pretreated with 100 mg/kg b.w. of vitamin C, and then dosed with CPF at a dose of 10.6 mg/kg b.w., 30 min later. The different treatment regimens were orally administered daily for a period of 17 weeks. Blood collected from the animals at the end of the test period were analyzed for erythrocyte osmotic fragility and malonaldehyde (MDA) concentration as an index of lipid peroxidation. The study showed that CPF caused significant increase in erythrocyte fragility and MDA concentration, which were ameliorated by pretreatment with vitamin C. In conclusion, the study showed that CPF-evoked erythrocyte fragility due to increased lipoperoxidative changes was ameliorated by pretreatment with vitamin C.

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Human and experimental animal studies have shown long- and short-term neurological sequelae following acute organophosphate (OP) exposure. Although the main molecular mechanism of OP neurotoxiicty involves acetylcholinesterase (AChE) inhibition, studies have also implicated the induction of oxidative stress. The present study was therefore aimed at evaluating the effect of acute chlorpyrifos (CPF) exposure on short-term sensorimotor and cognitive changes in Wistar rats, the role of brain lipoperoxidative changes and the effect of pretreatment with vitamin C. Twenty-eight rats divided into four groups of seven rats in each group served as subjects for this study. Rats in group I were given soya oil (2 ml/kg) while those in group II were dosed vitamin C (100 mg/kg). Group III were administered CPF only (42.5 mg/kg ∼50% of LD(50)), while group IV were pretreated with vitamin C (100 mg/kg) and then exposed to CPF (42.5 mg/kg), 30 min later. The regimens were administered once orally and the animals were examined for clinical signs, death and subjected to periodic neurobehavioral evaluation for motor strength, coordinated gait, neuromuscular coordination, learning and memory. At the end of 8 weeks of evaluation, the rats were sacrificed and the brain tissue evaluated for AChE activity and malonaldehyde (MDA) concentration, as an index of lipoperoxidative changes. The rats administered with CPF showed deficits in motor strength, coordinated gaits, neuromuscular coordination, learning and memory, slight decrease in AChE activity and an increase in brain MDA concentration. Pretreatment with vitamin C improved the neurobehavioral deficits and AChE activity, and caused a significant reduction in MDA concentration. In conclusion, the study has demonstrated that acute CPF exposure in Wistar rats caused short-term impairment in sensorimotor and cognitive functions partly due to brain lipoperoxidative changes, which were ameliorated by pretreatment with vitamin C.