Primary Research On Wnt/β-catnin Signaling Pathway In Regulation Of Procine Skeletal Muscle Fiber Types Changed

The number of skeletal muscle fiber and types have influence on the meat quality of livestock. There were divided into slow oxidative, fast oxidative, fast glycolytic and intermediate type according to the metabolism and contractile function of postnatal porcine, respectively, by different myosin heavy chain(MyHC) isormers of MyHC-I, MyHC-IIa, MyHC-IIb and MyHC-IIx determined. The number of skeletal muscle fiber were determined porcine prenatal, it be will depend on skeletal muscle satellite cells differentiation and muscle fiber type transformation in the future development. Study how to effectively control the satellite cells directional differentiation and regulate of fiber type composition to improve the meat quality has important practical significance. Wnt/β-catenin signaling pathway which plays an important role to regulate muscle growth and development. Currently, it has not been reported that the role of Wnt/β-catenin signaling pathway regulated composition of postnatal porcine skeletal muscle fiber type. Therefore, this study used histological methods, such as frozen sections of HE staining, Oil red O staining, mATPase staining, immunohistochemical staining, and molecular biology techniques of Real time PCR and Western Blotting to identify morphology and histology development regularity of porcine skeletal muscle. Studying of relate genes expression pattern in Wnt/β-catenin signaling pathway during porcine skeletal muscle development. Using 15 mMol/L LiCl treatment of satellite cells with single isolated muscle fiber. To utilize cell biology and molecular biology techniques ,such as Western Blotting and immunofluorescence staining, to investigate of Wnt/β-catenin signaling pathway in porcine satellite cells differentiation in vitro. The main results are as follows:1. The cross sectional area of skeletal muscle fiber increased during porcine development. The slow muscle transformed into fast muscle and slow muscle fiber significantly smaller than fast muscle fiber. The capacity of polyester in SOL was better than LD and EDL, and have more slow muscle fiber.2. The mRNA expression levels of MyHC-I, GSK-3β,β-catenin and Fz3 decreased with the development of LD, MyHC-IIb increased, MyHC-IIa increased from 1-day old to 2weeks then decreased, MyHC-IIx did not change significantly. The protein expression levels of slow muscle,β-catenin and p-GSK-3βas same as the mRNA, while p-β-catenin, GSK-3βand fast muscle increasd. The protein expression levels ofβ-catenin and slow muscle in SOL were the highest, there were the lowest in EDL at 6-month old, in contrast of fast muscle protein.3. 15 mMol/L LiCl induced skeletal muscle satellite cells differentiation into slow muscle fiber. The protein expression levels of p-GSK-3β,β-catenin, myosin and slow muscle increased, p-β-catenin, GSK-3βand fast muscle decreased, and the endogenousβ-catenin in nuclear increased.In summary, the skeletal muscle fiber cross sectional area gradually increased during development, and the area of fast muscle fiber was significantly larger than slow. The capacity of polyester in SOL was better than LD and EDL, and have more slow muscle fiber. The result found that Wnt/β-catenin signaling pathway promotes the porcine slow muscle fiber to growth. Wnt signaling pathway promoted satellite cells to myogenic differentiation when it was activitied by LiCl, and induced satellite cells differentiation to slow muscle fiber.