The effects of growth factors on bovine satellite cells

This study examined the effects of basic fibroblast growth factor (bFGF), insulin-like growth factor I (IGF-I) and transforming growth factor beta (TGF-β) on the proliferation and differentiation of bovine satellite cells (BSC) in vitro. Cells were treated with serum-free defined media containing varying concentrations of bFGF, IGF-I and TGF-β. On day 3 of treatment total cell nuclei and myotube nuclei were determined. bFGF stimulated BSC proliferation in a dose-dependent fashion with half-maximal stimulation observed at a concentration of 5 ng/ml (p < .05). Similar results were found for IGF-I and TGF-β in the presence of FGF, with half-maximal stimulation observed at 5 ng/ml and 1 ng/ml, respectively. With regard to differentiation, TGF-beta inhibited myotube formation at concentrations above 0.05 ng/ml. IGF-I stimulated myotube formation at concentrations as low as 10 ng/ml (p < .05). These results demonstrate that proliferation and differentiation of BSC in vitro are affected by growth factors, and consequently, similar effects may be found in vivo. This information may prove to be useful in future methods of manipulating muscle growth in vivo