Gene and protein expressions of vimentin and desmin during embryonic development of the mylohyoid muscle

Abstract

Meckel's cartilage is known to be involved in formation of the prenatal mandible. However, the relationship between Meckel's cartilage and the embryonic mylohyoid muscle during growth and development has been investigated only rarely. This study examined the expression of intermediate filaments in Meckel's cartilage and the embryonic mylohyoid muscle in fetal mice during morphological development. Specimens of E12-16 ICR mice sectioned in the frontal direction were subjected to immunohistochemistry for vimentin and desmin. Hematoxylin and eosin sections showed that the immature mylohyoid muscle began to grow along Meckel's cartilage during fetal development. Weak vimentin expression was detected in the mylohyoid muscle and surrounding tissues at E12. Desmin expression was detected specifically in the mylohyoid, and strong expression was evident after E13, and increased with age. It was inferred that the mylohyoid muscle is one the tissues developing from Meckel's cartilage, the latter exerting a continuous influence on the growth of the former. In the early stage, the surrounding mesenchymal tissues expressing vimentin formed a scaffold for the developing mylohyoid muscle. Muscle attachment at E13 showed steady desmin expression, which continued until maturity. This study suggested the possibility that Meckel's cartilage has an influence not only on the mandibular bone, but also on the development of the mylohyoid muscle attached to the mandibular bone. Furthermore, it revealed a stage of the developmental process of the mylohyoid muscle in which the expression of vimentin, which is a common protein in the surrounding tissue such as muscle and bone, induces the morphological formation of the mylohyoid muscle, cooperating with the surrounding structures.

Expression of Intermediate Filaments in the Development of Genioglossus Muscle

“…Moreover, the expression of desmin at E12 during which separation of the tongue and mandible was noted indicates that desmin is has a functional at this stage. This coincides with previous studies that vimentin and desmin are involved in the growth of skeletal muscles 7,[12][13][14]16) . Separation of the tongue from the mandible started at E12 although it was still incomplete at this point.…”

“…Vimentin is specific in mesenchymal cells and considered to be deeply involved in building tissues. In contrast, desmin is considered to be specifically expressed in muscle but not in premature tissues 5,7) . The expression of vimentin at E11 in which there was no separation of the mandible and the tongue indicates that vimentin is important in the development of these tissues.…”

“…Recently, desmin has been found to be strongly expressed in skeletal muscle and bone attachment 7) .…”

Medial Pterygoid initiated the Growth of the Mandible through Premature Muscle Contraction

“…The influence of the MC to the development of other muscles specifically the mylohyoid has been shown recently 1) . Three powerful muscles constituting the muscles of mastication are attached to the mandibular bone responsible for its intricate movements.…”

“…which both exist in skeletal muscles 1) . Desmin has also been reported to be present in costameres existing at the membranes overlying Z-disks and M bands 17) .…”