Immunohistochemical identification of TGF-β1 at the maxillaries in growing Sprague–Dawley rats and after muscle section

Growth factors are currently being extensively studied in the literature to ascertain their role during maxillofacial development. Taking into account that few investigations refer to the functions of growth in the maxillaries, our aim was to identify the TGF-β1 immunohistochemical expression pattern in the maxillaries of growing rats. A secondary aim was to identify this pattern after orofacial function inhibition by muscle section. In the palate and the mandibular symphysis and body, we found that bone was formed through an endomembranous pathway with intense TGF-β1 staining inside chondroid cells during the maximum development stages. At the midpalatal suture and the mandibular symphysis and condyle, endochondral ossification was detected with an intense expression of TGF-β1 inside the chondrocytes when major growth occurred. After the muscle had been sectioned, at the mandible the maturation process was accelerated, this change being transitory until muscular function was recovered. However, at the palate, the intervention caused a greater disturbance of the growing pattern, which did not recover normality.