Biochemical and histological changes in rat liver caused by cypermethrin and beta-cyfluthrin.

Cypermethrin and beta-cyfluthrin are two most widely used multipurpose pyrethroids. After determining their oral LD50 (416.98 mg kg-1 and 354.8 mg kg-1 body weight, respectively), we assessed their hepatotoxicity in Wistar rats following acute (0.1 LD50 for 1 day) and sub-acute (0.1 LD50 for 7, 14, 21 or 28 days) poisoning. The assessment was based on hepatic marker enzymes AST, ALT, LDH, ALP, glycogen, total proteins, total lipids, cholesterol, free fatty acids, and phospholipids. AST, ALT, LDH, total lipids, cholesterol, phospholipids, and free fatty acids in hepatic homogenate increased following pyrethroid stress. In contrast, hepatic proteins, glycogen, and ALP activity decreased due to lysis of structural proteins and leakage of enzymes into the blood stream. Biochemical data were consistent with histological alterations (cytoplasmic vacuolisation, nuclear polymorphism, eccentric nucleus, karyolysis, karyorrhexis, and sinusoidal dilation). Comparatively greater hepatocellular damage was noted in beta-cyfluthrin than in cypermethrin-treated rats, which is probably related to the fluorine atom in beta-cyfluthrin.