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Abstract - 215 - Summary In the present work. we have studied the toxic effect of two of the widely used insecticides namely fenvalerate which belongs to the pyrethroid insecticides and malathion which belongs to the organophosphorous insecticides, on adult albino rats of both sexes. Our study included comparative between ti’l:!effectsof acute and short term chronic toxicities of the two insectecides. The biochemical fmdings in our investigation included SOOT, SOPT, alk. phosphatase, bilirubin, urea and creatinine. The histopathological changes were studied in liver, kidney and heart. Moreover, determination ofLD of both fenvalerate and 50 malathion were determined. In the present work 200 animals were used. These were classified into two main big groups. First Group : Acute toxicity groups; Which were subdivided into; _ - 216 - a) Control group; of 8 rats in which SGPT, SGOT, alk. phosphatase, bilirubin, urea and creatinine were determined. b) Fenvalerate group; 48 rats were divided into 6 groups each of 8 rats, in which fenvalerate was given in increasing doses of 200, 400, 600, 800, 1000, 1200 mg / kg.b.w. respectively. And it was found that LD was 600 mg 50 /kg. b.w. And there were histopathological changes in liver such as central and focal necrosis, central vien congestion, sinusoidal dilatation, hydropic degeneration, lymphocytic infilteration, bile duct proliferation. This histopathological changes were directly proportional to the increase of the dose. There was significant increase in SOOT, SGPT, alk, phosphatase and bilirubin, The biochemical changes confirm our histopathological changes. This may be explained by accumulation of mucopolysaccharides and mixed function oxidation in hepatic cells which leads to the damage of the liver cells and causes the above mentioned histopathological and biochemical changes. There were also histopathological changes in the kidney such as tubular necrosis, accumulation of non cellular material, interstitial haemorrages, lymphocytic infilteration, shrunken and necrotic glomeruli, congestion and hydropic swelling. ----- - 217 - These histopathological changes were directly proportional to the increase of the dose. There was significant increase in blood urea and serum creatinine which confirmed our histopathological changes. This could be explained by accumulation of the metabolites of fenvalerate leading to the damage of the kidney glomeruli and the appearance of unusual cytoplasmic inclusion bodies c) Malathion group : 48 rats were divided into 6 groups each of 8 rats, in which malathion was given in increasing doses of 400, 200, 1200, 1600, 2000, and 2400 mg / kg b.w respectively. And it was found that LD was 1200 mg / kg b.w. 50 There were histopathological changes in both liver and kidney as those in case of fenvalerate treated rats but with higher degree. Histopathological changes also were directly proportional to the increase of the dose. Biochemical changes in case of malathion treated rats confirmed the histopathological studies. These changes may be due to accumulation of the metabolities of malathion such as alkyl phosphate and phenolic - 218 - metabolities which lead to damage of kidney cells and impairment of its function. Also both activation and detoxication reactions of malathion lead to disturbance in the cytochrome P. 450 mono oxygenase system, leading to congestion and necrosis and histopathological changes in liver cells and impairment of its function. Secound Group : Short - term Chronic toxicity groups; In these groups 96 animals were used, they were subdiveded into (a) fenvalerate treated group and (b) malathion treated group each group received 1 / 10 ill which was, 50 in case of fenvalerate treated group equal to 60 mg / kg. b.w. and in malathion treated group equal to 120 mg / kg. b.w. Histopathological and biochemical studies were investigated weekly on 8 animals in each fenvalerate treated group and malathion treated group. a) Fenvalerate treated groups; There were histopathological changes, as mentioned before in acute cases, in liver and kidney and these changes were increased in percentage after the 2 lli!. 3 rd and 4 !h week, i.e, histopathological changes were directly proportional to the length - 219 - of period, Biochemical changes were significally increased which confirmed our histopathological changes. This could be explained, as mentioned before, by accumulation of mucopolysaccharides and mixed function oxidation in hepatic cells and due to accumulation of the metabolites of fenvalerate leading to damage to kidney glomeruli and appearance of unusual cytoplasmic inclusion bodies. b) Malathion treated groups; There were histopathological changes as mentioned before in acute cases in liver and kidney, but it is here more prominant than in case of fenvalerate treated rats. It was noticed that the histopathological changes in malathion treated rats were directly proportional to the length of period. Biochemical changes were significal1y increased which confirmed our histopathological changes. This may be explained, as mentioned before, due to accumulation of the metabolites of malathion and its, detoxication reactions. This leads to disturbance of the cytochrome P. 450 monooxygenase system in liver. Moreover, it was noticed that there were no significant histopathological lesions in the heart in case of both Malathion and Fenvalerate acute and short term chronic toxicity except a - 220 - 50% of the animal’s hearts that showed congestion as a part of general venous congestion which occured before death. from the histopathological and biochemical results obtained from Malathion and Fenvalerate treated rats in acute and short term chronic toxicity we noticed that Fenvalerate is less toxic than Malathion. The Pyrethroids are rapidly metabolized and these compounds are incompletely absorbed from gastrointestinal tract, These compounds are neither skin irritants, nor skin sensitisers and inhalation toxicity is fairly low. |