The aim of this study was to determine the effect of a sub-acute 4-week exposure to methidathion (MD) on the hematological system and hepatic integrity of rats. We also assessed whether co-administration of micronutrients such as selenium (Se) and zinc (Zn) prevented MD-induced hepatic damage. Rats were randomly divided into four groups of six each: the first group served as a control which received standard diet, the second group received both Se (0.5mg/kg of diet) and Zn (0.227 g/l drinking water), the third group received only MD (5 mg/kg b.w. by gavage using corn oil as a vehicle), and the fourth group received MD and combined selenium and zinc. After four weeks, exposure to MD induced a significant increase in plasmatic activities of AST, ALT, ALP, LDH, and liver malondialdehyde level. In contrast, reduced glutathione level (GSH), and the activities of catalase (CAT), superoxide dismutase (SOD), and the glutathione peroxidase (GPx) content of hepatic tissue decreased significantly. Moreover, treatment with Se and Zn in MD-treated rats maintained all the biochemical parameters cited above. In conclusion, the obtained results indicate the ability of Se and Zn to attenuate the MD-induced liver and erythrocytes oxidative damage.  
Key words: Biochemical studies, liver, methidathion, oxidative stress, rat, selenium, zinc.   

Methidathion (MD) is an organophosphate insecticide and acaricide used in both agricultural and urban areas throughout the world including Algeria. The objective of this study was to evaluate the protective effect of Artemisia campestris (Ac) leaf aqueous extract on sub-acute four-week’s oxidative damage induced by MD on the hematological system and renal integrity of rats. The animals were randomly divided into four groups of seven each: group I served as control which received standard diet; group II received only Ac (5g/l) while the third group received only MD (5mg/kg b.w.by gavage using corn oil as vehicle). Rats in the fourth group (MD+Ac) were treated with MD and Ac extract. Results showed that lipid peroxidation increased significantly in MD-treated rats, as evidenced by high renal malondialdehyde (MDA) levels. As well as, the activities of glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathion-s-transferase (GST), catalase (CAT), and the level of reduced glutathione (GSH) content in renal tissue decreased by MD. On the other hand, a significant increase in plasmatic levels of total protein, urea and creatinine levels was observed in MDtreated group. However, the treatment of Ac extract with MD-treated rats has maintained the biochemical parameters cited above. The changes in hematological and biochemical parameters were substantiated by histological data. In conclusion, our results indicated a possible mechanism of MD-induce nephrotoxicity and plasma biomarkers were disturbed. Artemisia campestris leaf aqueous extract ameliorated the toxic effects of this pesticide in renal tissue suggesting their role as potential antioxidants. Keywords: Methidathion, Artemisia campestris, Biochemical studies, Kidney, Oxidative stress, Rat.