Abstract
Nonalcoholic steatohepatitis (NASH) is regarded as a hepatic manifestation of the metabolic syndrome which can progress to hepatic cirrhosis and hepatocellular carcinoma. It is thought that matrix metalloproteinases (MMPs) play an important role in hepatic fibrosis and we previously reported a correlation between oxidative stress and MMP-9 expression. However, the expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in the progression of NASH is unclear. In this study we used spontaneously hypertensive and hyperlipidemic rats (SHHR) fed a high-fat diet and 30% sucrose solution (HFDS) as a model for NASH, in order to clarify the relationships between oxidative stress, liver weight (LW), MMPs and TIMPs at various time-points in the progression of NASH. Male SHHR and Sprague-Dawley (SD) rats were divided into four groups: SHHR-normal diet (ND), SHHR-HFDS, SD-ND and SD-HFDS. Hepatic fibrosis was clearly increased at 13 months in SHHR-HFDS, resembpling NASH. LW and oxidative stress markers in plasma were increased in SHHR-HFDS compared to the other groups. Oxidative stress was correlated with LW in all rats. Expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 mRNA, measured by real-time polymerase chain reaction, was increased in the liver of SHHR-HFDS at 13 months. This study suggests that oxidative stress, MMPs and TIMPs may play an important role in the progression of NASH.
