title: Molecular changes in detrained & retrained adult jaw muscle.
abstract: A hypofunctional masticatory system was developed in 21-day-old male rats by feeding them a soft diet for 27 weeks. Retraining of a parallel group for 6 weeks was achieved by switching back to a hard diet after 21 weeks. A control group was fed a hard diet for 27 weeks. At the end of the experimental period, the expression levels of the myosin heavy chain isoform genes MYH 1 and 2 (fast), 3 (embryonic) and 7 (slow) in the deep masseter were compared using qRT-PCR analysis. The gene expressions of MYH 3 and MYH 7 were significantly higher in the rehabilitation group compared with the normal and hypofunctional group, but no significant differences were found in regards to the gene expression of MYH 1 and 2. Retraining made it possible for the slow (MYH 7) isoform levels to adapt to the increased mechanical load. The increased level of embryonic (MYH 3) isoform could be due to the need of creation of new MYH isoforms.
authors.affiliation: Department of Orthodontics, Institution of Odontology, The Sahlgrenska Academy at the University of Gothenburg, Sweden.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Ödman
authors.forename: Nigel P
authors.initials: NP
authors.lastname: Hunt
authors.forename: Hadwah A
authors.initials: HA
authors.lastname: Matloub Moawad
authors.forename: Andrea C M
authors.initials: AC
authors.lastname: Sinanan
authors.forename: Stavros
authors.initials: S
authors.lastname: Kiliaridis
authors.forename: Mark P
authors.initials: MP
authors.lastname: Lewis
mesh_terms: D000818:Animals; D004032:Diet; D004435:Eating; D015870:Gene Expression; D007568:Jaw / Q000502:physiology; D008297:Male; D008334:Mandible / Q000502:physiology; D008406:Masseter Muscle / Q000378:metabolism / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C000594638:MYH7 protein, rat; C510384:Myh3 protein, rat; D020033:Protein Isoforms; D018995:Myosin Heavy Chains