Abstract: 【Objective】Follistatin can regulate skeletal muscle hypertrophy and fat deposition, and promote proliferation of the skeletal muscle satellite cell. The study intends to use in vitro recombination follistatin to treat the duck skeletal muscle satellite cell, which can be proved that the functional mechanism of TGF-β/smad signaling pathway is playing a role in its proliferation process.【Method】 Based on differential centrifugation technology, skeletal muscle satellite cells isolated from embryonic 14-day ducks were treated by proliferation medium containing 0,1,10 and 100 ng·mL^-1 follistatin, respectively, after the cells density reached 70%-80% confluence. After incubation for 36 h, the degree of skeletal muscle satellite cells proliferation were tested by CCK-8. The cells were identified by immunofluorescence staining with pax7 antibody. Real-time qPCR was performed to measure the genes of expression differntiation including proliferation marker gene PCNA, and myogenic MyoD, smad2/3, TGF-βcaused by follistatin supplement.【Result】Under the inverted microscope, ti was found that a part of duck skeletal muscle cells did not adhere to round, a of cells part of cells adhered to fusiform 12 hours of culture. Adherent cell number increased and cells slightly longer after 24 h. Cells completely adherent, and fusiform, on day 2. The cell number increased, some cells differentiated, after 3 days. The number of cells further was increased, the cells thicker, some cells started to fuse after 4 days. A small amount of cells began differentiation, and further fusion of the cell on day five. The result of immunofluorescence staining showed that pax7 in more than 95% of the skeletal muscle satellite cells was positive, and the population of cells stained with Pax7 was suggested that the group of 10 ng·mL^-1 follistatin was significantly higher than the control group (P＜0.01). The gene expression analysis showed that compared with the control group, the expression level of MyoD in 10 ng·mL^-1 follistatin treated group was significantly decreased (P＜0.05), whereas, the expression levels of PCNA, TGF-β and Smad2 in follistatin treated groups were significantly increased (P＜0.05). The expression of Smad3 gene ultimately significantly increased (P＜0.01). Results of detection of protein expression by Western blotting showed that compared with the control group, TGF-β protein and Smad2/3 phosphorylat ion protein levels were also significantly increased.【Conclusion】Results of study suggested that follistatin promoted the expression of PCNA gene and reduced MyoD gene expression in duck skeletal muscle satellite cell. Furthermore, follistatin raised the expression of TGF-β, Smad2/3. Generally, 10 ng·mL^-1 concentration of follistatin could significantly promote proliferation of the duck skeletal muscle satellite cell, the same that TGF-β / Smad signaling pathway maybe play a important role in it.

Key words: Follistatin, skeletal muscle satellite cell, proliferation, duck