Abstract
The objective of this article was to evaluate in vitro effect of grape seed procyanidin extract (GSPE) on differentiation, proliferation, and lipolysis of porcine adipocytes, providing a molecular basis for the use of GSPE in pig fat regulation. Primary preadipocytes isolated from subcutaneous adipose tissue of pigs were used as the in vitro cell model. Treatment of GSPE repressed preadipocyte differentiation, as evidenced by reduced lipid accumulation, decreased mRNA expressions of peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid-binding protein 4 (FABP4), as well as enhanced expressions of preadipocyte factor-1. Activity of glycerol-3-phosphate dehydrogenase (GPDH), one of the most important enzymes in the pathway for triacylglycerol biosynthesis, was also decreased. Furthermore, GSPE could suppress preadipocyte proliferation by inducing G0/G1 cell cycle arrest and cell apoptosis. In porcine mature adipocytes, treatment with GSPE attenuated lipid content and GPDH activity, and the release of both free fatty acid and glycerol were enhanced; mRNA expressions of key lipolytic transcription factors, including hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), were elevated in GSPE-treated adipocytes. In summary, our results suggest GSPE inhibits porcine preadipocyte differentiation and proliferation and stimulates lipolysis of mature adipocytes, thus providing novel insights for further exploring the use of GSPE as a fat accumulation inhibitor.