Muscle Plasticity: Changes in Oral Function of Muscle Fiber Characteristics

To clarify changes in oral function and its relation to muscle fiber characteristics, we evaluated changes in isoforms of the myosin heavy chain as a muscle contraction protein in the mouse masseter, temporalis, and tongue muscles after weaning. As a result, all muscles showed changes in muscle fiber characteristics immediately after weaning, i. e., at the initiation of mastication, increasing the number of isoforms. This finding was marked in the temporalis muscle. In addition, when mechanical stress was applied to myoblasts, the numbers of myoblasts and nuclei in each myoblast increased, and muscle fiber characteristics also changed.