Scopoletin 보충이 만성 알코올을 급여한 흰쥐의 인슐린저항성 및 항산화방어계에 미치는 영향

Abstract

This study investigated the effects of scopoletin (6-methoxy-7-hydroxycoumarin) supplementation on insulin resistance and the antioxidant defense system in chronic alcohol-fed rats. Rats were fed a Lieber-Decarli liquid diet containing 5% ethanol with or without two doses of scopoletin (0.01 and 0.05 g/L) for 8 weeks. Pair-fed rats received an isocaloric carbohydrate liquid diet. Chronic alcohol did not affect fasting serum glucose levels, although it induced glucose intolerance and hyperinsulinemia compared with the pair-fed group and led to insulin resistance. Both doses of scopoletin similarly improved glucose intolerance, serum insulin level, and insulin resistance. Scopoletin supplementation significantly activated phosphatidyl inositol 3-kinase, which was inhibited by chronic alcohol. Two doses of scopoletin up-regulated hepatic mRNA expression and activity of glucokinase as well as down-regulated mRNA expression and activity of glucose-6-phosphatase compared with the alcohol control group. Both doses of scopo- letin significantly reduced cytochrome P450 2E1 activity and elevated aldehyde dehydrogenase 2 activity, resulting in a lower serum acetaldehyde level compared with the alcohol control group. Chronic alcohol suppressed hepatic mRNA expression and activities of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione perox- idase; however, they were reversed by scopoletin supplementation, which reduced hydrogen peroxide and lipid peroxide levels in the liver. These results indicate that dietary scopoletin attenuated chronic alcohol-induced insulin resistance and activated the antioxidant defense system through regulation of hepatic gene expression in glucose and antioxidant metabolism.