Abstract
Sirtuin type 1 (SIRTl) and AMP-activated protein kinase (AMPK) play important roles in regulating energy metabolism, cell proliferation and differentiation, ageing, apoptosis, and metabolism. The effect of 100, 200, and 400 μm Resveratrol (RES), an activator of SIRT1, on apoptosis of bovine intramuscular adipocytes was investigated by nuclear staining, flow cytometry, quantitative real-time polymerase chain reaction, and western blotting. Results show that RES inhibited adipogenesis, decreased cell viability, and increased apoptotic rates in a dose-dependent way. RES up-regulated SIRT1, AMPKα, forkhead box O1 (FOXO1), hormone-sensitive lipase (HSL), lipoprotein lipase (LPL), caspase-3, and Bax; and down-regulated peroxisome proliferator-activated receptor-gamma (PPARγ), fatty acid synthase (FAS), and Bcl-2, at both mRNA and protein level. The effect of RES was abolished by addition of sirtinol (an inhibitor of SIRT1). This is the first study demonstrating a role for AMPK-SIRT1-FOXO1 signalling pathway in regulating apoptosis in bovine intramuscular adipocytes. Our findings provide important information on the mechanism by which RES controls deposition of cattle intramuscular fat via adipocyte apoptosis.