Vocal fold bowing and thyroarytenoid myocyte size in aging rats
In this rat study, 18- and 24-month-old animals showed more vocal fold bowing than 4-month-olds, and their thyroarytenoid myofibers were larger, not smaller. [1]
Automatic summary · not editorially reviewed
The key findings
Bowing Index was higher in 18- and 24-month rats than in 4-month rats. [1]
Mean myofiber minimum Feret diameter and cross-sectional area were larger at 18 and 24 months than at 4 months, with no difference between 18 and 24 months. [1]
The authors say aged rats' increased bowing parallels clinical findings in age-related vocal atrophy and propose future mechanism studies. [1]
The source at a glance
- Study type / format
- Preclinical animal study (abstract).
- Population / context
- Sprague-Dawley rats aged 4, 18 and 24 months (n = 24).
- Summary based on
- Study abstract
- Original publication
- September 25, 2026
Rat ages and vocal fold bowing measured
The study compared Sprague-Dawley rats aged 4, 18 and 24 months (n = 24). Endoscopic video of the vocal folds was scored with a Bowing Index by two independent reviewers. The Bowing Index was higher in 18-month rats than in 4-month rats (mean difference 7.15, 95% confidence interval 4.39–9.90) and also higher in 24-month rats than in 4-month rats (mean difference 4.26, 95% confidence interval 1.50–7.01). The abstract does not report a direct 18- versus 24-month comparison for bowing.
Supporting source [1]
Larger thyroarytenoid myofibers in older rats
The thyroarytenoid muscles were analyzed for myofiber number, minimum Feret diameter and cross-sectional area. Mean minimum Feret diameter was 19.8 ± 1.3 μm at 4 months, 22.1 ± 1.7 μm at 18 months and 22.5 ± 1.5 μm at 24 months. Mean cross-sectional area was 435.8 ± 49.4 μm, 535.2 ± 81.3 μm and 556.6 ± 54.3 μm at 4, 18 and 24 months. Both measures differed between 4 and 18 months and between 4 and 24 months, but not between 18 and 24 months. So the older rats had larger myofibers, which the authors note rather than atrophy.
Supporting source [1]
Rat model parallels clinical findings, mechanisms open
The authors conclude that aged rats showed increased vocal fold bowing, which they describe as paralleling findings in age-related vocal atrophy in people. They also report increased myofiber size in aged rats. The abstract states that future studies will examine mechanisms behind increased myofiber size together with bowing, including shifts in muscle fiber type, compensatory hypertrophy and altered mitochondrial function. These are proposed future directions, not established causes.
Supporting source [1]
How to interpret this
This is an abstract only; the full text was not reviewed. It reports a rat model with 24 animals across three age groups, so it cannot establish causes of human age-related vocal atrophy or confirm that rats mirror human laryngeal aging. The abstract gives no direct 18- versus 24-month bowing comparison and no myofiber number results.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Miller CS, Jaleel Z, Kim BS, Al-Ghezi M, Leong S, Bhatt NK. · europepmc.org · September 25, 2026