Restoring vocal fold movement after transection and immediate suturing of the recurrent laryngeal nerve with local application of basic fibroblast growth factor: an experimental study in the rat.
OBJECTIVE
To evaluate the effects of basic fibro-blast growth factor (bFGF) on the recovery of vocal fold movement and the attenuation of laryngeal muscle atrophy after transection of the recurrent laryngeal nerve (RLN).


METHODS
Quantitative assessment of vocal fold movement using the video cassette recorder (VCR) image-analysis method and histologic examination of the laryngeal muscle.


METHODS
Fifty-eight Wistar rats underwent RLN transection and one of the following three procedures: 1) transection of the RLN alone (transection group, n = 18), 2) suture of the nerve stumps followed by local administration of phosphate-buffered saline (PBS) solution using an osmotic pump (PBS group, n =20), or 3) suture of the nerve stumps followed by local administration of bFGF (FGF group, n = 20). Vocal fold movements were recorded with VCR by way of a rigid endoscope, and the VCR images were analyzed on a computer. Histologic changes in the thyroarytenoid (TA) muscle were evaluated by measuring the cross-sectional area of the muscle and average size of muscle fibers.


RESULTS
In the transection group, vocal fold movement did not recover, and atrophy of the TA muscle gradually progressed after sectioning the nerve. In contrast, vocal fold movement as assessed by VCR image-analysis recovered in some cases in the immediate suturing groups, more markedly in the FGF group (34.1 +/- 29.1%) than in the PBS group (5.5 +/- 7.9%) (P <.05). Histologically, atrophy of the laryngeal muscle was significantly attenuated by the local administration of bFGF.


CONCLUSIONS
bFGF facilitates regeneration of the transected RLN and attenuation of intrinsic laryngeal muscle atrophy, thereby restoring laryngeal function.
Motoyoshi
Kazumi
K
Department of Otolaryngology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, Ehime, Japan.
Hyodo
Masamitsu
M
Yamagata
Takahiko
T
Gyo
Kiyofumi
K
D000818:Animals; D005346:Fibroblast Growth Factors / Q000494:pharmacology*; D008297:Male; D009334:Neck Muscles / Q000294:innervation; D009416:Nerve Regeneration / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D061226:Recurrent Laryngeal Nerve Injuries; D014826:Vocal Cord Paralysis / Q000188:drug therapy* / Q000503:physiopathology*; D014827:Vocal Cords / Q000503:physiopathology*
D005346:Fibroblast Growth Factors