Nonalcoholic steatohepatitis (NASH) is a disease closely associated with
obesity and diabetes. A prevalence of
type 2 diabetes and a high body mass index in
cryptogenic cirrhosis may imply that
obesity leads to
cirrhosis. Here, we examined the effects of an extract of Ecklonia cava, a brown algae, on the activation of high
glucose-induced hepatic stellate cells (HSCs), key players in hepatic
fibrosis. Isolated HSCs were incubated with or without a high
glucose concentration. Ecklonia cava extract (ECE) was added to the culture simultaneously with the high
glucose. Treatment with high
glucose stimulated expression of
type I collagen and α-smooth muscle actin, which are markers of activation in HSCs, in a dose-dependent manner. The activation of high
glucose-treated HSCs was suppressed by the ECE. An increase in the formation of intracellular
reactive oxygen species (ROS) and a decrease in intracellular
glutathione levels were observed soon
after treatment with high
glucose, and these changes were suppressed by the simultaneous addition of ECE. High
glucose levels stimulated the secretion of bioactive
transforming growth factor-β (TGF-β) from the cells, and the stimulation was also suppressed by treating the HSCs with ECE. These results suggest that the suppression of high
glucose-induced HSC activation by ECE is mediated through the inhibition of ROS and/or GSH and the downregulation of TGF-β secretion. ECE is useful for preventing the development of diabetic
liver fibrosis.