The regulatory effects of fish oil and chitosan on hepatic lipogenic signals in high-fat diet-induced obese rats
Chen-Yuan Chiu a,b, Tien-Chia Chang c, Shing-Hwa Liu b,d,e,*,
Meng-Tsan Chiang c,*
a Department of Cell and Tissue Engineering, Changhua Christian Hospital, Changhua, Taiwan
b Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
c Department of Food Science, College of Life Science, National Taiwan Ocean University, Keelung, Taiwan
d Department of Pediatrics, College of Medicine and Hospital, National Taiwan University, Taipei, Taiwan
e Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
The present study investigated the regulatory effects of fish oil and chitosan on the signals of hepatic lipid metabolism and the postulated mechanism in high-fat diet-induced obese rats. Diet supplementation of chitosan and fish oil efficiently suppressed the increased weights in body and livers of high-fat diet-fed rats. Supplementation of chitosan and fish oil significantly decreased the activities of hepatic lipid biosynthesis-related enzymes and efficiently regulated plasma lipoprotein homeostasis. Both chitosan and fish oil significantly ameliorated the alterations in the protein expressions of hepatic lipogenic transcription factors (LXRα and PPARα), and could also significantly regulate the downstream hepatic lipogenic genes (FAS, HMGCR, CYP7A1, FATP, FABP, AOX, and ABCA) expressions in high-fat diet-fed rats. These results suggest that both fish oil and chitosan exerts downregulative effects on hepatic lipid metabolism in high-fat diet-induced obese rats via the LXRα inhibition and PPARα activation, which further affect the expressions of hepatic lipogenesis-associated genes.
Keywords: chitosan, fish oil, gene expressions, high-fat diet, lipogenesis