Exploring the expression of MMP-2, MT1-MMP, and MMP-9 in the pectoral muscle of Ross chickens during E11, E15, and E19 of fetal development.

There are pertinent studies on the relationship between matrix metalloproteinases (MMPs) and muscle cell differentiation in vitro, but currently, there are few in vivo studies exploring MMP expression in chicken muscle during different stages of differentiation. Therefore, we aimed to investigate in vivo whether MMP-2, MT1-MMP, and MMP-9 are expressed in the pectoral muscle during the fetal stages of Ross chicken development on days E11, E15, and E19. Our results demonstrated that, in contrast to earlier reports in vitro, myocyte fusion occurs on E11, while on E15 and E19, secondary muscle wave formation is occurring. MMP-2, on the other hand, appears to be expressed more than MT1-MMP throughout the evaluated days, whereas MMP-9 is not expressed at any point. Additionally, serine was discovered as an unexpected finding in the zymogram analysis. In conclusion, considering the experimental limitations of the present study, it was found that MMP-9 is not expressed during the evaluated ages of in vivo pectoral muscle development in Ross chickens, indicating a limited role for this enzyme in muscle differentiation during the fetal period. In contrast, the expression of MMP-2 and MT1-MMP is crucial, as these are detected from myocyte fusion at E11 to the development of myotubes observed at E19, reflecting their significant role in muscle differentiation within the Ross chicken lineage.