Increased Expression of MuRF1 Is Associated with Radiation-induced Laryngeal Muscle Atrophy.
BACKGROUND
Laryngeal muscles play an important role in breathing, sound production and trachea protection against food. Laryngeal dysfunctions during radiotherapy for head and neck cancers are common. In the present study, we aimed to investigate the early effect of radiation on the laryngeal muscles in vivo and possible mechanisms involved in this process.


METHODS
Eight-week-old female C57bl/ mice received neck irradiation with a single dose of 25 Gy and bilateral thyroarytenoid (TA) muscles of mice were collected at day 3, 7 and 10 post-irradiation for evaluating muscle size, myosins, myosin heavy chain (MyHC) composition and MuRF1 protein levels.


RESULTS
A significant reduction in the size of muscle fibers and myosins in the TA muscles were observed at days 3, 7, 10 after radiation (p<0.05). The loss of IIB myosin was more severe than that of IIA/X myosins at day 7 post-irradiation (75% vs. 64%). MuRF1 protein level was markedly increased at day 7 and 10 after radiation (p<0.05).


CONCLUSIONS
Radiation induced an acute muscle fiber atrophy and myosin loss in the intrinsic laryngeal muscles. MuRF1 may play an important role in the radiation-induced protein degradation in the laryngeal muscles and warrants further investigation.
Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC, U.S.A. Department of Head and Neck Surgery, Tangshan People's Hospital, Shengli Road, Tangshan, HeBei, P.R. China.
Xiaochen
X
Han
Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC, U.S.A.
Leonardo
L
Pires
Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC, U.S.A.
J Dale
JD
Browne
Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC, U.S.A.
Christopher A
CA
Sullivan
Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, U.S.A. xfeng@wakehealth.edu wzhao@wakehealth.edu.
Weiling
W
Zhao
Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC, U.S.A. xfeng@wakehealth.edu wzhao@wakehealth.edu.
Xin
X
Feng
D000818:Animals; D015153:Blotting, Western; D002588:Cesium Radioisotopes / Q000009:adverse effects*; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects*; D007124:Immunoenzyme Techniques; D007821:Laryngeal Muscles / Q000378:metabolism* / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D009124:Muscle Proteins / Q000378:metabolism*; D009133:Muscular Atrophy / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*
D002588:Cesium Radioisotopes; D009124:Muscle Proteins; D000070584:Tripartite Motif Proteins; C499084:Trim63 protein, mouse; D044767:Ubiquitin-Protein Ligases
Laryngeal muscle; MuRF1; myosin; radiation