Age-related changes in rat genioglossus, geniohyoid and masseter muscles

摘要

ObjectivesThe aim of this study was to elucidate age-related changes from adult to middle age in the contractile properties of the masseter, genioglossus and geniohyoid muscles of the rat. Materials and Methods We analysed the expressions of myosin heavy chain (MyHC) mRNAs and proteins as indicators of the contractile properties in these muscles obtained from rats at 6, 12, 18 and 24 months of age using real-time PCR and SDS-PAGE. Results We found no marked age-related changes in the expressions of MyHC mRNAs and proteins in rat masseter and geniohyoid muscles, suggesting that the biological ageing process does not affect contractile properties in these muscles. However, we found a decrease in the expression of MyHC IIb mRNA with ageing in the rat genioglossus muscle, suggesting that biological ageing process induces at least some fast-to-slow myofibre phenotype transition. Conclusion The biological ageing process from adult to middle age appears to differentially affect different types of craniofacial muscles.