Mami Kaneko1, Takuya Tsuji2, Yo Kishimoto2, Yoichiro Sugiyama1, Tatsuo Nakamura3, Shigeru Hirano4. 1. Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan. 2. Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 3. Department of Regeneration Science and Engineering, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan. 4. Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan. Electronic address: hirano@koto.kpu-m.ac.jp.
Abstract
OBJECTIVES: Vocal fold atrophy following unilateral vocal fold paralysis is caused by atrophy of the thyroarytenoid (TA) muscle and remains a challenge. Medialization procedures are popular treatment options; however, hoarseness often remains due to the reduction in mass or tension of the TA muscle. Therefore, in addition to medialization procedures, TA muscle reinnervation is desirable. In vivo studies have shown the potential for basic fibroblast growth factor (bFGF) to affect muscular and nerve regeneration. The present study aimed to examine the regenerative effects of bFGF on restoration of TA muscle atrophy caused by recurrent laryngeal nerve transection. STUDY DESIGN: Prospective animal experiments with controls. METHODS: TA muscle atrophy was induced by unilateral transection of the recurrent laryngeal nerve. One month after transection, different doses (200 ng, 100 ng, 10 ng) of bFGF in 50 µL were repeatedly injected into the TA muscle four times with an interval of 1 week between injections. Saline only was injected in the sham group. Larynges were harvested for histologic and immunohistochemical examination 4 weeks after the final injection. RESULTS: The cross-sectional TA muscle area was significantly larger in the bFGF-treated groups compared with the sham-treated groups. Immunohistochemistry indicated that bFGF significantly increases the number of neuromuscular junctions and satellite cells in the TA muscle. CONCLUSIONS: These results suggest that local application of bFGF to the TA muscle may improve TA muscle atrophy caused by recurrent laryngeal nerve paralysis. Furthermore, bFGF may have regenerative effects on both nerves and muscles.
OBJECTIVES: Vocal fold atrophy following unilateral vocal fold paralysis is caused by atrophy of the thyroarytenoid (TA) muscle and remains a challenge. Medialization procedures are popular treatment options; however, hoarseness often remains due to the reduction in mass or tension of the TA muscle. Therefore, in addition to medialization procedures, TA muscle reinnervation is desirable. In vivo studies have shown the potential for basic fibroblast growth factor (bFGF) to affect muscular and nerve regeneration. The present study aimed to examine the regenerative effects of bFGF on restoration of TA muscle atrophy caused by recurrent laryngeal nerve transection. STUDY DESIGN: Prospective animal experiments with controls. METHODS: TA muscle atrophy was induced by unilateral transection of the recurrent laryngeal nerve. One month after transection, different doses (200 ng, 100 ng, 10 ng) of bFGF in 50 µL were repeatedly injected into the TA muscle four times with an interval of 1 week between injections. Saline only was injected in the sham group. Larynges were harvested for histologic and immunohistochemical examination 4 weeks after the final injection. RESULTS: The cross-sectional TA muscle area was significantly larger in the bFGF-treated groups compared with the sham-treated groups. Immunohistochemistry indicated that bFGF significantly increases the number of neuromuscular junctions and satellite cells in the TA muscle. CONCLUSIONS: These results suggest that local application of bFGF to the TA muscle may improve TA muscle atrophy caused by recurrent laryngeal nerve paralysis. Furthermore, bFGF may have regenerative effects on both nerves and muscles.