Relationship of Expression of Lean Related Genes and Growth of Skeletal Muscle Cells in Nuogu Pig Breed

The aim of this study was to explore the regulation of myostatin (MSTN),cyclin-dependent-kinase 2 (CDK2),insulin-like growth factor 2 (IGF2) and hormore sensitive lipase (HSL) genes on skeletal muscle cells growth and fat metabolism in local pig breeds. Taking Yorkshire×Landrace crossbreed pig as control,local varieties Nuogu pig from Guizhou province was chosen for the experiment,and the expression of MSTN,IGF2,HSL and activity of CDK2 were detected in the skeletal muscle cells by RT-PCR and immunohistochemistry methods. The results showed that the expression of MSTN mRNA in Nuogu pig tended to be higher than that in the crossbreed pig (P0.05) and the expression of IGF2 mRNA in Nuogu pig was higher than that in the crossbreed pig (P0.01),but the expression of HSL mRNA was lower (P0.05). Brown granules of MSTN,IGF2 and HSL were detected in the cytoplasm of muscle cells from Nuogu and the crossbreed pig. Compared with the crossbreed pig,signal of MSTN and IGF2 proteins was much more intensive (P0.05),but HSL expression and CDK2 activity were weaker in Nuogu pig (P0.01). These results of correlation analysis indicated that the higher expression of MSTN and IGF2 together with the lower CDK2 activity decreased the number of muscle cells. Higher MSTN and IGF2 expression enlarged the fiber size of muscle cells in Nuogu pig breed. Furthermore,lower HSL and higher IGF2 made the fat deposition much easier in Nuogu pig than that in the Yorkshire×Landrace crossbreed pig. Altogether,4 factors,MSTN,CDK2,IGF2 and HSL,cooperated with each other and resulted in the lower lean percentage in the native Nuogu pig breed in Guizhou province.