A Rat Excised Larynx Model of Vocal Fold Scar

• Published in: Journal of speech, language, and hearing research language, and hearing research, 2009-08, Vol.52 (4), p.1008-1020
• Main Authors: Welham, Nathan V, Montequin, Douglas W, Tateya, Ichiro, Tateya, Tomoko, Choi, Seong Hee, Bless, Diane M
• Format: Article
• Language: English
• Subjects: Acoustics; Air Pressure; Amplitude (Acoustics); Analysis of Variance; Animals; Anti-Inflammatory Agents, Non-Steroidal - therapeutic use; Biomedical research; Changes; Cicatrices; Cicatrix - drug therapy; Cicatrix - physiopathology; Collagen Type I - metabolism; Collagen Type III - metabolism; Comparative Analysis; Dependent Variables; Disease Models, Animal; Experimental Groups; Experiments; Fibroblast Growth Factor 2 - therapeutic use; Flow velocity; Glottis - physiopathology; Health services; Human Body; Hyaluronic Acid - metabolism; Immunohistochemistry; In Vitro Techniques; Injuries; Laboratory animals; Laryngeal Diseases - drug therapy; Laryngeal Diseases - physiopathology; Laryngology; Larynx; Literary Devices; Male; Phonation - physiology; Phonation threshold pressure; Phonology; Predictor Variables; Rats; Rats, Sprague-Dawley; Rodents; Therapy; Vibration; Vocal cords; Vocal Cords - drug effects; Vocal Cords - injuries; Vocal Cords - physiopathology; Vocal folds
• ISSN: 1092-4388; 1558-9102
• DOI: 10.1044/1092-4388(2009/08-0049)

Douglas W. Montequin The National Center for Voice and Speech, The Denver Center for the Performing Arts, Colorado Ichiro Tateya Tomoko Tateya Kyoto University, Japan Seong Hee Choi Diane M. Bless University of Wisconsin School of Medicine and Public Health, Madison Contact author: Nathan V. Welham, University of Wisconsin School of Medicine and Public Health, K4/723 CSC, 600 Highland Avenue, Madison, WI 53792. E-mail: welham{at}surgery.wisc.edu . Purpose: To develop and evaluate a rat excised larynx model for the measurement of acoustic, aerodynamic, and vocal fold vibratory changes resulting from vocal fold scar. Method: Twenty-four 4-month-old male Sprague–Dawley rats were assigned to 1 of 4 experimental groups: chronic vocal fold scar, chronic vocal fold scar treated with 100-ng basic fibroblast growth factor (bFGF), chronic vocal fold scar treated with saline (sham treatment), and unscarred untreated control. Following tissue harvest, histological and immunohistochemical data were collected to confirm extracellular matrix alteration in the chronic scar group; acoustic, aerodynamic, and high-speed digital imaging data were collected using an excised larynx setup in all groups. Phonation threshold pressure ( P th ), glottal resistance ( R g ), glottal efficiency ( E g ), vibratory amplitude, and vibratory area were used as dependent variables. Results: Chronically scarred vocal folds were characterized by elevated collagen Types I and III and reduced hyaluronic acid abundance. Phonation was achieved, and data were collected from all control and bFGF-treated larynges; however, phonation was not achieved with 3 of 6 chronically scarred and 1 of 6 saline-treated larynges. Compared with control, the chronic scar group was characterized by elevated P th , reduced E g , and intralarynx vibratory amplitude and area asymmetry. The bFGF group was characterized by P th below control-group levels, E g comparable with control, and vocal fold vibratory amplitude and area symmetry comparable with control. The sham group was characterized by P th comparable with control, E g superior to control, and vocal fold vibratory amplitude and area symmetry comparable with control. Conclusions: The excised larynx model reported here demonstrated robust deterioration across phonatory indices under the scar condition and sensitivity to treatment-induced change under the bFGF condition. The improvement observed under the sham condition may reflect unanticipated therapeutic benefit