The combination of S-adenosylmethionine and dilinoleoylphosphatidylcholine attenuates nonalcoholic steatohepatitis produced by a high-fat diet in rats

Abstract

In the pathogenesis of non-alcoholic steatohepatitis (NASH), oxidative stress resulting from free radicals generated by cytochrome P4502E1 (CYP2E1) plays a major role suggesting the importance of antioxidants. The objective of this study was to assess in a high-fat diet (HF) rat model the effects of the combination of s-adenosylmethionine (SAMe) plus dilinoleoylphosphatidylcholine (DLPC) in the treatment of NASH. To test the hypothesis that these two antioxidants are beneficial in NASH, male Sprague-Dawley rats were fed five different diets for six weeks: control, HF diet and HF plus SAMe and DLPC or their combination. As expected, the HF diet significantly increased hepatic triacylglycerols and CYP2E1 levels. However, only the combination diet opposed this effect, consistent with different actions of the two antioxidants. Next, 24 additional rats divided in two groups were fed the HF or the HF+SAMe+DLPC diets for 3 weeks. Dietary intake was similar, but liver triacylglycerols dropped from 76.1+/-6.8 to 49.4+/-3.5 mg/g (p=0.002) and hepatic CYP2E1 mRNA decreased after treatment (p=0.01) with a trend for less CYP2E1 protein. This was accompanied by a 41% reduction of hepatic 4-hydroxynonenal (4-HNE) (p=0.008), reflecting control of oxidative stress. Furthermore, the hepatic inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) mRNA and TNF-alpha protein decreased (p=0.05 and p=0.01 respectively) with attenuation of alpha1(I) procollagen mRNA and type I collagen levels (p=0.01 and p=0.02, respectively). We concluded that the combination SAMe+DLPC might be beneficial in NASH by reducing oxidative stress and associated liver injury.