Crocin attenuates CCl4-induced liver fibrosis via PPAR-γ mediated modulation of inflammation and fibrogenesis in rats

Liver fibrosis is a chronic pathological condition with a leading cause of liver-related mortality worldwide. In the present study, we have evaluated the antifibrotic effect of crocin, a carotenoid present in the stigma of Crocus sativus, and also explored its putative mechanism of action.Liver fibrosis was induced by intraperitoneal administration of 30% carbon tetrachloride (CCl4). The crocin was administered orally at 20, 40 and 80 mg/kg body weight along with CCl4 up to 8 weeks.Chronic exposure to CCl4 resulted in elevated levels of liver enzymes and reduced cytochrome P450 2E1 (CYP2E1) activity in the liver. The liver tissue showed cellular swelling, vacuolization, necrosis, infiltration of inflammatory cells and fibrotic changes. The crocin treatment significantly lowered the levels of liver enzymes in serum and improved the liver CYP2E1 mRNA levels. The pathological changes in the liver were also lowered by crocin treatment. The level of pro-inflammatory cytokines, nuclear factor-kappa B, interleukin-6 and tumor necrosis factor α and fibrogenic factor, transforming growth factor β, and α-smooth muscle actin were elevated by the CCl4 in the liver tissue. However, crocin treatment at different doses significantly reduced the expression of these factors. The increased caspase 3/7 activity was also lowered by crocin. CCl4 administration decreased the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) in liver tissue. The improved PPAR-γ expression in the liver by crocin treatment indicates its role in the therapeutic effect of crocin.Crocin attenuated the various events in the progression of liver fibrosis via PPAR-γ mediated modulation of inflammatory and fibrogenic pathways.