Inhibition of endoplasmic reticulum stress in high-fat-diet-induced obese C57BL/6 mice: Efficacy of a novel extract from mulberry (Morus alba) leaves fermented with Cordyceps militaris

Abstract

A few clues about correlation between endoplasmic reticulum (ER) stress and mulberry (Morus alba) leaves were investigated in only the experimental autoimmune myocarditis and streptozotocin-induced diabetes. To investigate whether a novel extract of mulberry leaves fermented with Cordyceps militaris (EMfC) could suppress ER in fatty liver, alterations in the key parameters for ER stress response were measured in high fat diet (HFD)-induced obese C57L/6 mice treated with EMfC for 12 weeks. The area of adipocytes in the liver section were significantly decreased in the HFD+EMfC treated group as compared to the HFD+Vehicle treated group, while their level was higher in HFD+Vehicle treated group than No treated group. The level of the eukaryotic initiation factor 2 alpha (eIF2α) and inositol-requiring enzyme 1 beta (IRE1α) phosphorylation and CCAAT-enhancer-binding protein homologous protein (CHOP) expression were remarkably enhanced in the HFD+Vehicle treated group. However, their levels were restored in the HFD+EMfC treated group, although some differences were detected in the decrease rate. Similar recovery was observed on the ER stress-induced apoptosis. The level of Caspase-3, Bcl-2 and Bax were decreased in the HFD+EMfC and HFD+orlistat (OT) treated group compared to the HFD+Vehicle treated group. The results of the present study therefore provide first evidence that EMfC with the antiobesity effects can be suppressed ER stress and ER stress-induced apoptosis in the hepatic steatosis of HFD-induced obesity model.