Quercetin ameliorate insulin resistance and up-regulates cellular antioxidants during oleic acid induced hepatic steatosis in HepG2 cells

• Published in: Toxicology in vitro Vol. 27; no. 2; pp. 945 - 953
• Main Authors: Vidyashankar, Satyakumar, Sandeep Varma, R., Patki, Pralhad Sadashiv
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-03-2013
• Subjects: Alanine Transaminase - metabolism; Albumins - metabolism; Antioxidants - pharmacology; Cytokines - metabolism; DNA Fragmentation; Fatty Liver - chemically induced; Fatty Liver - metabolism; Glucose - metabolism; Glutathione; Glutathione - metabolism; Hep G2 Cells; HepG2 cells; Humans; Insulin Resistance; Lipid Peroxidation - drug effects; Non-alcoholic fatty liver disease; Oleic Acid; Quercetin; Quercetin - pharmacology; RNA, Messenger - metabolism; TNF-alpha; Tumor Necrosis Factor-alpha - genetics; Up-Regulation; Urea - metabolism; Oleic acid; TNF-alpha; Quercetin; Insulin resistance; HepG2 cells; Non-alcoholic fatty liver disease; Glutathione
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2013.01.014

► 2mM Oleic acid induced hepatic steatosis in HepG2 cells. ► Quercetin ameliorates insulin resistance which is major indication during NAFLD. ► Fat accumulation was decreased and cell proliferation was increased by quercetin. ► Quercetin inhibit IL-8 and TNF-alpha with increased cellular glutathione. ► First evidence regarding pharmacological action of quercetin to overcome NAFLD.
Hepatic lipid accumulation and oxidative stress contribute to non-alcoholic fatty liver disease (NAFLD). Thus, we hypothesized that the hypolipidemic and antioxidant activity of quercetin would attenuate events leading to NAFLD. Addition of 2.0mM oleic acid (OA) into the culture media induced fatty liver condition in HepG2 cells by 24h. It was marked by significant accumulation of lipid droplets as determined by Oil-Red-O (ORO) based colorimetric assay, increased triacylglycerol (TAG) and increased lipid peroxidation. The inflammatory cytokines TNF-α and IL-8 levels were significantly increased with decreased antioxidant molecules. OA induced insulin resistance which was evident by inhibition of glucose uptake and cell proliferation. Quercetin (10μM) increased cell proliferation by 3.05 folds with decreased TAG content (45%) and was effective in increasing insulin mediated glucose uptake by 2.65 folds. The intracellular glutathione content was increased by 2.0 folds without substantial increase in GSSG content. Quercetin (10μM) decreased TNF-α and IL-8 by 59.74% and 41.11% respectively and inhibited generation of lipid peroxides by 50.5%. In addition, RT-PCR results confirmed quercetin (10μM) inhibited TNF-alpha gene expression. Further, superoxide dismutase, catalase and glutathione peroxidase activities were increased by 1.68, 2.19 and 1.71 folds respectively. Albumin and urea content was increased while the alanine aminotransferase (ALAT) activity was significantly decreased by quercetin. Hence, quercetin effectively reversed NAFLD symptoms by decreased triacyl glycerol accumulation, insulin resistance, inflammatory cytokine secretion and increased cellular antioxidants in OA induced hepatic steatosis in HepG2 cells.