Response of masticatory muscles to passive stretch stimulus - from perspectives of functional appliances.
10.4041/kjod.2012.42.2.64
- Author:
Eung Kwon PAE
1
Author Information
1. Department of Orthodontics and Pediatric Dentistry, University of Maryland, School of Dentistry, Baltimore, MD, USA. epae@umaryland.edu
- Publication Type:Original Article
- Keywords:
Extensor digitorum longus;
Masticatory muscles;
Myosin heavy chains;
Stretch
- MeSH:
Animals;
Blotting, Western;
Contractile Proteins;
Extremities;
Humans;
Incisor;
Male;
Mandible;
Masticatory Muscles;
Muscles;
Myosin Heavy Chains;
Phenotype;
Rabbits
- From:The Korean Journal of Orthodontics
2012;42(2):64-72
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVE: The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. METHODS: Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed after 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). RESULTS: The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins after 7 days. CONCLUSIONS: The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.
