OBJECTIVES/HYPOTHESIS: Aging is associated with muscle fiber hypotrophy and decreased percentages of rapidly contracting myosin heavy chain (MyHC) type IIb muscle fibers. Tongue exercise programs used to treat dysphagia target age-related decline in tongue muscle function, but the impact of exercise on the intrinsic tongue muscles is unknown. We hypothesized that exercise would induce muscle fiber hypertrophy and increase the percentage of MyHC IIa fibers in the intrinsic tongue. STUDY DESIGN: Animal model. METHODS: Eight old and eight young-adult rats underwent 8 weeks of tongue exercise training, and 8 animals of each age group served as controls. Longitudinal, transverse, and verticalis muscle samples from the anterior, middle, and posterior regions of the tongue were sectioned and stained to determine muscle fiber diameter and MyHC composition. RESULTS: MyHC fiber type distribution was altered by exercise, and the effects differed by muscle and region of the tongue. In the exercise groups, as compared to the control groups, the anterior transverse and middle superior longitudinal muscles had significantly reduced percentages of MyHC IIx positive fibers and higher percentages of rapidly contracting fatigable MyHC IIb positive muscle fibers, whereas the middle transverse and posterior longitudinal muscles had increased percentages of the less rapidly contracting and more fatigue-resistant MyHC IIa fibers. The impact of exercise did not differ with age, as there was no significant interaction between age and exercise. Tongue exercise had no significant effect on muscle fiber diameter. CONCLUSIONS: The impact of exercise varied among the tongue muscles, which may indicate different functional contributions to the tongue exercise task. LEVEL OF EVIDENCE: NA Laryngoscope, 128:2245-2251, 2018.
OBJECTIVES/HYPOTHESIS: Aging is associated with muscle fiber hypotrophy and decreased percentages of rapidly contracting myosin heavy chain (MyHC) type IIb muscle fibers. Tongue exercise programs used to treat dysphagia target age-related decline in tongue muscle function, but the impact of exercise on the intrinsic tongue muscles is unknown. We hypothesized that exercise would induce muscle fiber hypertrophy and increase the percentage of MyHC IIa fibers in the intrinsic tongue. STUDY DESIGN: Animal model. METHODS: Eight old and eight young-adult rats underwent 8 weeks of tongue exercise training, and 8 animals of each age group served as controls. Longitudinal, transverse, and verticalis muscle samples from the anterior, middle, and posterior regions of the tongue were sectioned and stained to determine muscle fiber diameter and MyHC composition. RESULTS:MyHC fiber type distribution was altered by exercise, and the effects differed by muscle and region of the tongue. In the exercise groups, as compared to the control groups, the anterior transverse and middle superior longitudinal muscles had significantly reduced percentages of MyHC IIx positive fibers and higher percentages of rapidly contracting fatigable MyHC IIb positive muscle fibers, whereas the middle transverse and posterior longitudinal muscles had increased percentages of the less rapidly contracting and more fatigue-resistant MyHC IIa fibers. The impact of exercise did not differ with age, as there was no significant interaction between age and exercise. Tongue exercise had no significant effect on muscle fiber diameter. CONCLUSIONS: The impact of exercise varied among the tongue muscles, which may indicate different functional contributions to the tongue exercise task. LEVEL OF EVIDENCE: NA Laryngoscope, 128:2245-2251, 2018.
Authors: M A Nicosia; J A Hind; E B Roecker; M Carnes; J Doyle; G A Dengel; J Robbins Journal: J Gerontol A Biol Sci Med Sci Date: 2000-11 Impact factor: 6.053
Authors: S Schiaffino; L Gorza; S Sartore; L Saggin; S Ausoni; M Vianello; K Gundersen; T Lømo Journal: J Muscle Res Cell Motil Date: 1989-06 Impact factor: 2.698
Authors: Erika R Murphy; Rebecca Thompson; Kate L Osman; Chandler Haxton; Margaret Brothers; Li Lee; Kristen Warncke; Catherine L Smith; Amy N Keilholz; Ali Hamad; Mojgan Golzy; Filiz Bunyak; Lixin Ma; Nicole L Nichols; Teresa E Lever Journal: Front Neurosci Date: 2022-06-30 Impact factor: 5.152
Authors: Olívia Maria Costa Figueredo; Mariana Barbosa Câmara-Souza; Talita Malini Carletti; Maria da Luz Rosário de Sousa; Renata Cunha Matheus Rodrigues Garcia Journal: Int Dent J Date: 2020-01-09 Impact factor: 2.607
Authors: Miranda J Cullins; Julie M Wenninger; Jared S Cullen; John A Russell; Jeffrey A Kleim; Nadine P Connor Journal: Front Neurosci Date: 2019-12-19 Impact factor: 4.677
Authors: Tiffany J Glass; Joanie E Figueroa; John A Russell; Brittany N Krekeler; Nadine P Connor Journal: Front Physiol Date: 2021-10-21 Impact factor: 4.566