Deltamethrin (DLM), a widely used pyrethroid insecticide, induces hepatotoxicity through oxidative stress, inflammation, and apoptosis. This study investigated the protective effects of quercetin against DLM-induced liver injury in rats. Twenty male Wistar rats were randomly assigned to four groups: Sham, Que (50 mg/kg quercetin), DLM (5 mg/kg deltamethrin), and DLM-Que. Treatments were administered orally once daily for 5 weeks. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured to assess liver function. Oxidative stress markers (GSH, SOD, CAT, and MDA), inflammatory (IL-1β, TNF-α, and NF-κB) and apoptosis-related (caspase-3, bax, and bcl-2) gene expression were evaluated in liver tissue. Histopathological and stereological analyses were also performed. DLM administration caused marked hepatic injury, characterized by histopathological alterations, elevated ALT, AST, and MDA levels, reduced antioxidant enzyme activities, increased expression of inflammatory and pro- apoptotic genes, and decreased bcl-2 expression. Quercetin significantly attenuated these changes by restoring antioxidant status, suppressing inflammatory responses, and modulating apoptosis-related gene expression. Histological findings were supported by stereological data, showing significant improvements in hepatocyte density, sinusoidal length, and liver volume in the DLM-Que group compared with the DLM group. These findings demonstrate that quercetin protects against DLM-induced hepatotoxicity through regulation of oxidative stress, inflammation, and apoptosis and may represent a promising therapeutic strategy against pesticide-induced liver injury.
KEY WORDS: Quercetin; Deltamethrin; Hepatotoxicity; Oxidative stress; Apoptosis.
JU, H. & CHEN, W. Quercetin protects against deltamethrin-induced hepatotoxicity in rats: Histomorphometric and stereological evidence of reduced oxidative stress, inflammation, and apoptosis. Int. J. Morphol., 44(4):1320-1330, 2026.
