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The pathogenesis of nonalcoholic steatohepatitis (NASH) remains unclear, but accumulating data suggest oxidative stress and the relationship between inflammation and immunity plays a crucial role. The aim of this study is to investigate the spirulina, which is a blue-green algae rich in proteins and other nutritional elements, and its component-phycocyanin effect on a rat model of NASH. NASH model rats were established by feeding male Wistar rats with choline-deficient high-fat diet (CDHF) and intermittent hypoxemia by sodium nitrite challenge after 5 weeks of CDHF. After experimental period of 10 weeks, blood and liver were collected to determine oxidative stress injuries and efficacies of spirulina or phycocyanin on NASH model rats. In the NASH model rats, increase in plasma liver enzymes and liver fibrosis, increases in productions of reactive oxygen species from liver mitochondria and from leukocytes, the activation of nuclear factor-kappa B, and the change in the lymphocyte surface antigen ratio (CD4(+)/CD8(+)) were observed. The spirulina and phycocyanin administration significantly abated these changes. The spirulina or phycocyanin administration to model rats of NASH might lessen the inflammatory response through anti-oxidative and anti-inflammatory mechanisms, breaking the crosstalk between oxidative stress and inflammation, and effectively inhibit NASH progression.

Oxidative stress is frequently considered as a central mechanism of hepatocellular injury in non-alcoholic steatohepatitis (NASH). The aim of this study was to investigate the effects of fermented green tea extracts (FGTE) on NASH. Rats were fed a choline-deficient high-fat diet for 4 weeks to nutritionally generate fatty livers. NASH was induced chemically by oxidative stress using repeated intraperitoneal injections of nitrite. Rats with NASH developed steatohepatitis and liver fibrosis after 6-week of such treatment. At 10 weeks, blood and liver samples were collected from anesthetized animals and assessed for extent of OS injury and effects of FGTE, by biochemical, histological and histochemical analyses. FGTE reduced serum levels of liver enzymes, lipid peroxidation and production of mitochondrial reactive oxygen species. In addition, FGTE showed inhibition of progressions of cirrhosis. Our findings suggest that our FGTE have strong radical scavenging activity and may be beneficial in the prevention of NASH progression.

Recent reports described a high incidence of nonalcoholic steatohepatitis (NASH) in patients with obstructive sleep apnea. Accordingly, we hypothesized that recurrent and intermittent hypoxemia plays an important role in the pathogenesis of NASH. Our objective was construction of a practical and accurate experimental model to reproduce the key features of NASH in humans. Chemical hypoxemia through methemoglobinemia was induced by daily intraperitoneal injection of sodium nitrite (40 mg/kg) for 4 weeks in rats with fatty liver. The later was induced by 4-week feeding a choline-deficient high-fat diet (CDHF). Besides, the normal chow diets feeding groups were prepared with in the same manner except for CDHF feeding. The animal experiment was performed in four groups; Normal control, Hypoxemia, CDHF, and CDHF + hypoxemia. Nitrite was given for the later 4 weeks to each rat of Hypoxemia and CDHF + hypoxemia. CDHF + hypoxemia rats were confirmed to develop histological changes that resemble those of patients with NASH, together with biochemical liver dysfunction, while CDHF group was limited in mild steatosis, and Hypoxemia group liver was normal. Present study established a reproducible and useful NASH model resembling the main features of NASH in humans, and showed first that recurrent and intermittent hypoxemia aggravate fatty liver to steatohepatitis and liver fibrosis.