Anti-inflammatory and hepatoprotective effects of glycyrrhetinic acid on CCl₄-induced damage in precision-cut liver slices from Jian carp (Cyprinus carpio var. jian) through inhibition of the nf-kƁ pathway

In order to evaluate the antioxidant and anti-inflammatory effects of glycyrrhetinic acid (GA) on carbon tetrachloride (CCl₄)-induced damage in precision-cut liver slices (PCLS) from Jian carp (Cyprinus carpio. Jian), an acute liver damage model was established in this study. The viability of PCLS, levels of anti-oxidases in liver homogenates, expression of inflammation-related genes including nuclear factor-κB (nf-κB)/c-rel, inducible nitric oxide synthase (inos), interleukin-1β (il-1β), interleukin-6 (il-6) and interleukin-8 (il-8), and protein levels of (nf-κB)/c-rel in liver tissues were measured. The results showed that pretreatment of PCLS with GA at 5 and 10 μg/mL for 6 h significantly inhibited the cytotoxicity of CCl₄. GA attenuated CCl₄-induced oxidative stress in PCLS through promoting the recovery of superoxide dismutase (SOD) and glutathione (GSH) levels, and inhibiting malondialdehyde (MDA) synthesis. In inflammatory response, GA at both 5 and 10 μg/mL significantly inhibited the increase in mRNA levels of inflammatory cytokines including nf-kƁ/c-rel, inos, il-1β, il-6 and il-8, and the protein level of Nf-kƁ/C-rel induced by CCl₄. Furthermore, treatment with pyrrolyl dithiocarbamate (PDTC, 4 μg/mL), an inhibitor of nuclear transcription factor nf-kB, significantly inhibited nf-kB levels, and transcription of downstream cytokines inos, il-1β, il-6 and il-8, also the viability of PCLS was significantly increased. These results indicated that GA suppressed inflammation and reduced cytotoxicity by inhibiting the nf-kƁ signaling pathway, and plays a role in liver protection.