Green tea extract (GTE) reduces hepatic injury by inhibiting lipid accumulation and peroxidation in steatotic livers of obese mice

Abstract

Steatotic livers are vulnerable to oxidative insults that lead to hepatic lipid peroxidation and injury. Based on our finding that green tea extract (GTE) protected against hepatic steatosis and injury, we hypothesized that GTE would decrease hepatic lipid peroxidation and inflammation. Obese (ob/ob) mice (n = 38) were fed a diet containing GTE at 0, 0.5, or 1%, and lean mice (n = 12) were fed 0% GTE for 6‐wk. Then, hepatic lipid and malondialdehyde (MDA), serum alanine aminotransferase (ALT), and inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF)‐α were measured. Body weight was 33% greater (p<0.05) in obese compared to lean controls and was 18% lower in obese mice fed GTE at 1%. Hepatic lipid was 2.3‐times higher in obese mice and GTE at 1% reduced it by 13%. Hepatic MDA was 40% higher in obese compared to lean mice and GTE reduced it 16‐22%. Serum ALT was 7.3‐fold higher in obese controls and GTE at 1% decreased it 25%. MDA was correlated (p < 0.05) to ALT (r = 0.358) and total lipid (r = 0.383). Immunohistochemical evidence suggested that obese mice had greater hepatic iNOS expression and may be decreased with GTE at 1%. TNF‐α expression was unaffected by GTE. These data suggest that GTE protects against hepatic injury by decreasing hepatic lipid accumulation, peroxidation, and potentially obesity‐induced inflammation. Supported by a USDA‐NRI grant (2007‐02303) to RSB.Grant Funding SourceUSDA