Abstract
Liver damage and fibrosis are serious health problems without effective treatment. Proanthocyanidins (PAs) are flavonoids with several biological effects. We investigated the potential anti-fibrotic effect of proanthocyanidins on carbon tetrachloride (CCl4)-induced liver injury and fibrosis. Liver fibrosis was induced by oral administration of CCl4 three times a week for 5 and 9 weeks. PAs were daily administered in a dose of 500 mg/kg bw. Animals were divided into five groups: control groups, olive oil-treated group, Pas-treated group, CCl4-treated animals, and PAs + CCl4-treated rats. CCl4 and PAs were administered by gavage. Administration of CCl4 caused a significant elevation in alanine aminotransferase and aspartate aminotransferase activities, the concentration of alpha-2-macroglobulin, and bilirubin concentration. In addition, the protein and apolipoprotein contents were significantly decreased in the serum of CCl4-treated rats. These results were accompanied by histopathological alterations and increased inflammation, apoptosis, and DNA damage. Treatment with PAs caused remarkable regression of fibrosis and alpha-2-macroglobulin with improvement in histological characteristics of the liver after 5 and 9 weeks of intoxication. PAs could also maintain redox balance, evidenced by the prevention of lipid peroxidation and mitigation of the decrease in antioxidants. Treatment of intoxicated rats with PAs resulted in a significant decline in pro-inflammatory cytokines, including IL-6, IL-1β, and TNF-α in serum. This is associated with a remarkable decrease in apoptosis of hepatic cells shown by decreased levels of Bax, caspase-3, and -9, with increased Bcl-2. The protective effect of PAs was also evident by protecting DNA integrity in the intoxicated rats. PAs suppressed hepatic fibrosis, improved liver function and structure via modulating the interdependence between oxidative stress, inflammation, apoptosis, and DNA integrity in CCl4-treated rats.