Imidacloprid induced histological and biochemical alterations in liver of female albino rats

Imidacloprid is a neonicotinoid insecticide being used extensively for crop protection and pet flea control programmes. The effect of repeated oral administration of two doses of imidcloprid (1/10th and 1/50th of LD50 of imidacloprid) on liver of female albino rat was assessed. Histological examination of liver revealed that imidacloprid (1/10th of LD50) treatment resulted in dilations of central vein and sinusoids between hepatocytes however imidacloprid (1/50th of LD50) treatment did not induce histopathological changes in liver. Non significant decrease in alkaline phosphatase (AKP) activity was observed in imidacloprid treated rats. Liver aspartate aminotransferase level showed significant increase in higher dose of imidacloprid. Additionally, significant increases in plasma levels of aspatate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AKP) were observed in the treated rats. The results suggest that the higher doses of imidacloprid at 1/10th of LD50 is hepatotoxic as compared to lower dose of 1/50th of LD50 of imidacloprid.

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► Two doses of imidacloprid i.e. 45 and 9 mg/kg bw, which is 1/10th and 1/50th of LD50 were given to female albino rats for four weeks continuously by oral intubation.
► Weight of liver significantly decreased in 1/10th of LD50 treated rats and the microscopic examination of imidacloprid (1/10th and 1/50th of LD50) treated rat liver revealed many dose dependent degenerative changes of variable degrees in many areas of liver.
► AST, ALT and AKP activity increased significantly in plasma of 1/10th of LD50 treated rats but differed non-significantly in the plasma of rats treated with lower dose of imidacloprid.
► Treatment of rats with imidacloprid also caused changes in the enzyme levels of aspartate aminotransferase (AST) and alkaline phosphatase (AKP) in liver tissue.
► Imidacloprid at lower dose i.e. 9 mg/kg bw did not induce significant changes in liver architecture and biochemistry and may be considered as no observed effect level (NOEL) for female rats.