Grape seed proanthocyanidin extract ameliorates hepatic lipid accumulation and inflammation in grass carp (Ctenopharyngodon idella).

Hepatic lipid metabolism disorder due to excessive fat accumulation in fish is a significant problem in aquaculture. Studies have shown that grape seed procyanidin extract (GSPE) can regulate fish lipid metabolism and improve fish immunity. However, the mechanism is unclear. In this study, we used grass carp that stores excess fat in the liver as a model. In vitro, GSPE treatment of hepatocytes for 3 h significantly decreased TG content, accompanied with decreased expression of SREBP-1c, FAS, and ACC and increased expression of PPARα, ATGL, and LPL. GSPE treatment for 1 h significantly decreased expression of pro-inflammatory cytokines (TNFα, IL-6, IL-1β, and NF-κB) and increased the expression of anti-inflammatory cytokines (IL-10 and TGF-β1). In vivo, the administration of GSPE significantly reduced high-fat diet-induced increase of serum CHOL, TG, and HDL, but increased LDL content. GSPE treatment for 3 h increased expression of ATGL and LPL, and significantly decreased the expression of HFD-fed-induced SREBP-1c, ACC, FAS, PPARγ, PPARα, and H-FABP. GSPE treatment for 3 h also significantly decreased the expression of pro-inflammatory cytokines (TNFα, IL-6, and IL-1β) and increased the expression of the anti-inflammatory cytokine IL-10. The expression levels of the lipogenic miRNAs, miR-33, and miR-122, were suppressed both in vivo and in vitro by GSPE. In summary, GSPE had hypolipidemic and potential anti-inflammatory effects in the liver, potentially mediated by miR-33 and miR-122.