Eicosapentaenoic acid attenuates progression of hepatic fibrosis with inhibition of reactive oxygen species production in rats fed methionine- and choline-deficient diet.
OBJECTIVE
Nonalcoholic steatohepatitis (NASH) is associated with fat accumulation in the liver, and develops to cirrhosis with the progression of hepatic fibrosis. Eicosapentaenoic acid (EPA) is used to treat hyperlipidemia, and suppresses hepatic fat accumulation. As the effect of EPA on NASH remains unclear, we assessed the therapeutic effect of EPA and its mechanisms in an animal model of NASH.


METHODS
Wistar rats were fed a methionine- and choline-deficient (MCD) diet for 20 weeks, and given EPA ethyl ester (EPA-E, 1,000 mg/kg/day) or vehicle by gavage from week 12, at which hepatic fibrosis has already established. The liver was histologically analyzed for fibrosis and α-smooth muscle actin (αSMA) expression, and hepatic levels of transforming growth factor-β1 (TGF-β1), fibrogenic gene expression, reactive oxygen species (ROS), and triglyceride (TG) content were determined. Serum oxidative markers were also measured.


RESULTS
EPA-E treatment significantly suppressed the MCD-induced increase in fibrotic area of liver sections, with repressed macronodule formation. EPA-E also suppressed increases in hepatic fibrogenic factors, αSMA expression, TGF-β1 level, and messenger RNA (mRNA) levels of procollagens and connective tissue growth factor. EPA-E reduced MCD-induced increases in hepatic ROS level, serum oxidative markers, 8-isoprostane and ferritin, and hepatic TG content. Attenuation of hepatic fibrosis by EPA-E was significantly correlated with hepatic ROS level, but not TG content.


CONCLUSIONS
EPA-E attenuates progression of hepatic fibrosis in developed steatohepatitis, and this effect is likely mediated by inhibition of ROS production. These actions may elicit the therapeutic effect of EPA-E against NASH.
Kajikawa
Satoshi
S
Development Research, Pharmaceutical Research Center, Mochida Pharmaceutical Company Limited, 722 Uenohara, Jimba, Gotemba, Shizuoka, 412-8524, Japan. skaji@mochida.co.jp
Imada
Kazunori
K
Takeuchi
Takashi
T
Shimizu
Yutaka
Y
Kawashima
Akiko
A
Harada
Tsuyoshi
T
Mizuguchi
Kiyoshi
K
D000199:Actins / Q000032:analysis; D000818:Animals; D002796:Choline Deficiency / Q000378:metabolism*; D055513:Connective Tissue Growth Factor / Q000032:analysis; D018450:Disease Progression; D015118:Eicosapentaenoic Acid / Q000627:therapeutic use*; D005234:Fatty Liver / Q000178:diet therapy / Q000188:drug therapy; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008103:Liver Cirrhosis / Q000178:diet therapy / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008715:Methionine / Q000172:deficiency*; D065626:Non-alcoholic Fatty Liver Disease; D011347:Procollagen / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors*; D053773:Transforming Growth Factor beta1 / Q000032:analysis; D016896:Treatment Outcome; D014280:Triglycerides / Q000032:analysis
D000199:Actins; D055513:Connective Tissue Growth Factor; D015118:Eicosapentaenoic Acid; D008715:Methionine; D011347:Procollagen; D017382:Reactive Oxygen Species; D053773:Transforming Growth Factor beta1; D014280:Triglycerides; C498862:Acta2 protein, rat