Water Extract of Vitis coignetiae Pulliat Leaves Attenuates Oxidative Stress and Inflammation in Progressive NASH Rats

This study aimed to investigate the therapeutic effects of the water extract of leaves of Vitis coignetiae Pulliat (VCPL) on nonalcoholic steatohepatitis (NASH) with advanced fibrosis, as our previous study exhibited its preventive effect on NASH. The NASH animal model [PCT/JP2007/52477] was prepared by loading recurrent and intermittent hypoxemia stress to a rat with fatty liver, which resembled the condition occurring in patients with obstructive sleep apnea (OSA) and fatty liver, who have a high incidence of NASH. Intermittent hypoxemia stress is regarded as a condition similar to warm ischemia followed by re-oxygenation, which induces oxidative stress (OS). The daily 100 or 300mg/kg VCPL administrations were performed for 3 weeks perorally beginning at the time of detection of advanced liver fibrosis. The therapeutic efficacy of VCPL on NASH was demonstrated by the reduction of the leakage of hepato-biliary enzymes and the amelioration of liver fibrosis. The OS elevation in NASH rats was measured based on the derivation of reactive oxygen species from liver mitochondrial energy metabolism and on the decrease in plasma SOD-like activity. The aggravation of inflammatory responses was demonstrated by the neutrophil infiltration (elevated myeloperoxidase activity) and the progression of fibrosis in the livers of NASH rats. In addition, the NASH rats without VCPL treatment also exhibited activation of nuclear factor-κB, a key factor in the link between oxidative stress and inflammation. All of these changes were reduced dose-dependently by the VCPL administration. These findings indicate that VCPL may improve hepatic fibrosis or at least suppress the progression of NASH, by breaking the crosstalk between OS and inflammation.