Original Article
Copyright ©2011 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 21, 2011; 17(19): 2379-2388
Published online May 21, 2011. doi: 10.3748/wjg.v17.i19.2379
Inhibitory effect of schisandrin B on free fatty acid-induced steatosis in L-02 cells
Jian-Hong Chu, Hui Wang, Yan Ye, Ping-Kei Chan, Si-Yuan Pan, Wang-Fun Fong, Zhi-Ling Yu
Jian-Hong Chu, Hui Wang, Yan Ye, Ping-Kei Chan, Wang-Fun Fong, Zhi-Ling Yu, Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
Si-Yuan Pan, Department of Pharmacology, Beijing University of Chinese Medicine, Beijing 100015, China
Author contributions: Chu JH and Wang H contributed equally to this work; Yu ZL designed the research; Chu JH and Wang H performed the research; Ye Y, Chan PK, Pan SY and Fong WF provided the analytic tools and edited the manuscript; Chu JH, Wang H and Yu ZL wrote the paper.
Supported by The Hong Kong Baptist University, No. FRG/08-09/II-30
Correspondence to: Dr. Zhi-Ling Yu, Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China. zlyu@hkbu.edu.hk
Telephone: +852-34112465 Fax: +852-34112461
Received: August 12, 2010
Revised: August 13, 2010
Accepted: August 20, 2010
Published online: May 21, 2011
Abstract

AIM: To investigate the effects of schisandrin B (Sch B) on free fatty acid (FFA)-induced steatosis in L-02 cells.

METHODS: Cellular steatosis was induced by incubating L-02 cells with a FFA mixture (oleate and palmitate at the ratio of 2:1) for 24 h. Cytotoxicity and apoptosis were evaluated by 3-(4, 5-dmethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay and Annexin V/propidium iodide staining, respectively. Cellular total lipid was determined using a photocolorimetric method after Nile red staining, and triglyceride content was measured using an enzymatic kit. To study the effects of Sch B on steatosis, L-02 cells were treated with Sch B (1-100 μmol/L) in the absence or presence of 1 mmol/L FFA for 24 h, and cellular total lipid and triglyceride levels were measured. To explore the mechanisms of action of Sch B in the steatotic L-02 cells, mRNA levels of several regulators of hepatic lipid metabolism including adipose differentiation related protein (ADRP), sterol regulatory element binding protein 1 (SREBP-1), peroxisome proliferator-activated receptor (PPAR)-α and PPAR-γ were measured by quantitative real-time polymerase chain reaction (PCR), and protein levels of ADRP and SREBP-1 were measured by immunoblotting.

RESULTS: Treatment with 1 mmol/L FFA for 24 h induced intracellular lipid accumulation in L-02 cells comparable to that in human steatotic livers without causing apparent apoptosis and cytotoxicity. Sch B mitigated cellular total lipid and triglyceride accumulations in the steatotic L-02 cells in a dose-dependent manner. Quantitative real-time PCR and Western blot analyses revealed that treatment of L-02 cells with 100 μmol/L Sch B reverted the FFA-stimulated up-regulation of ADRP and SREBP-1.

CONCLUSION: Sch B inhibits FFA-induced steatosis in L-02 cells by, at least in part, reversing the up-regulation of ADRP and SREBP-1.

Keywords: Free fatty acid, Hepatic lipid metabolism, Hepatocellular steatosis, L-02 cells, Schisandrin B