The function of platelet-derived growth factor in the differentiation of mouse tongue striated muscle.

ABSTRACT

OBJECTIVE: To determine the function of platelet-derived growth factor (PDGF) in the final differentiation phase of tongue striated muscle cells. MATERIALS AND METHODS: We analyzed the expressions of PDGF-A, -B, platelet-derived growth factor receptor (PDGFR)-α, and PDGFR-ß in mouse tongues between embryonic days (E) 11 and 15. Furthermore, we examined the effects of human recombinant PDGF-AB and the peptide antagonist for PDGFRs using an organ culture system of mouse embryonic tongue. Mouse tongues at E12 were cultured in BGJb medium containing human recombinant PDGF-AB for 4 days or the peptide antagonist for PDGF receptors for 8 days. RESULTS: PDGF-A, -B, PDGFR-α, and -ß were expressed in the differentiating muscle cells between E11 and 15. The human recombinant PDGF-AB induced increases in the mRNA expressions of myogenin and muscle creatine kinase (MCK) and the number of fast myosin heavy chain (fMHC)-positive cells, markers for the differentiation of muscle cells. On the other hand, the peptide antagonist for PDGFRs induced suppressions in the mRNA expressions of myogenin and MCK, and the number of fMHC-positive cells. Both the PDGF-AB and the antagonist failed to affect the expressions of cell proliferation markers. CONCLUSION: These results suggest that PDGF functions as a positive regulator in the final differentiation phase of tongue muscle cells in mouse embryos.