Effect of Recombinant Adiponectin(rAdp) on Adiponectin, Adiponectin Receptors and Myosin Heavy Chain(MyHC) mRNA Expression in Muscle Satellite Cell of Wannanhua Pigs In vitro
Abstract：Adiponectin(Adp) is a cytokine secreted mainly by adipose tissue. The function of Adp has attracted recent interest. Skeletal muscle satellite cells were separated from semitendinosus muscle of Wannanhua pig at 10 days of age. Muscle satellite cells were treated with 0, 1, 5 and 10 μg/mL recombinant adiponectin(rAdp) respectively for 12 h or 24 h. Adp, AdpR1, AdpR2, four isoforms of myosin heavy chain (MyHCI, MyHC2a, MyHC2b and MyHC2x), AMP-activated protein kinase(AMPK) and peroxisome proliferator-activated receptor alpha (PPARa) mRNA levels were determined by Real-time fluorescence quantitative RT-PCR. The results showed that: (1) mRNA expression of Adp and AdpR1 treated with 1 μg/mL rAdp was significantly increased, and AdpR2 mRNA expression was even significantly increased only at 24 h. But mRNA expression of Adp, AdpR1 and AdpR2 treated with 5 and 10 μg/mL rAdp were lower; (2) mRNA expression of MyHC1 and MyHC2x treated with 1 μg/mL rAdp were significantly increased, but MyHC2b mRNA expression was significantly decresed only at 24 h. mRNA expression of MyHC2b treated with 5 and 10 μg/mL rAdp was significantly decresed, but MyHC1 mRNA expression had no significant change. mRNA expression of MyHC2a treated with 10 μg/mL rAdp was significantly decresed. MyHC2x mRNA expression treated with 5 μg/mL rAdp was incresed significantly. (3) mRNA expression of AMPK treated with 1, 5 and 10 μg/mL rAdp was significantly increased only at 12 h. However, the low rAdp doseage group had higher AMPK mRNA level. PPARa mRNA expression was significantly increased treated with 1 μg/mL rAdp. But high rAdp dosage groups had no this effects. The results suggest that the function of adiponectin to skeletal muscle may be related to activating both AMPK and PPARa signal pathways by binding adiponectin receptor. Adiponectin can change composition of muscle fibers by increasing MyHC1, MyHC2a and MyHC2x, and decreasing MyHC2b gene expression.
