Abstract:

The purpose of this study was to determine whether treatment of cultured C2 C12 myoblasts and mytotubes with TNF-? over time (24, 48 and 72hrs) would stimulate collagen metabolism either directly or indirectly through a TGF-?1 dependent pathway. We found that TNF-? treatment of C2 C12 myoblasts (regardless of dose) resulted in a significant decrease in type I collagen mRNA at each time point, however there was no impact on the level of TGF-?1 mRNA. In myotubes, significant decreases in type I collagen mRNA levels were observed at 24 and 48 hours in the TNF-? treatment group, but not at 72 hours. In contrast with the myoblasts, TNF-? resulted in a significant decrease in myotube TGF-?1 mRNA levels at all three time points. These findings show that muscle cells exposed to TNF-? in vitro do not respond by increasing TGF-?1 or type I collagen mRNA expression.