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Effects of Hypothyroidism on the Extracellular Matrix of the Vocal Folds of Adult Female Rats
Welber C Mororó1, Karine V G de Oliveira1, Jônatas B do Amaral1
1Department of Otorhinolaryngology, Head and Neck Surgery, Universidade Federal de São Paulo/Escola Paulista de Medicina (UNIFESP/EPM), Sao Paulo, Sao Paulo, Brazil.
Objective:
The aim of the present study was to investigate the changes in the extracellular matrix of the vocal folds of female rats after induction of hypothyroidism.
Study Design:
Prospective and experimental study.
Setting:
Single tertiary center.
Methods:
Female rats were divided into 2 groups: hypothyroid (after thyroidectomy and treatment with methimazole) and euthyroid (control). After 8-week experiment, the animals were euthanized and their vocal folds were removed. These were analyzed for the presence of collagen type I, collagen type III, and elastin using the enzyme-linked immunosorbent assay technique. An hyaluronan-binding protein isolated from bovine nasal cartilage was used to identify and isolate the hyaluronic acid for samples.
Results:
The hypothyroid group presented significantly increased serum TSH concentrations (P = .0425) and significantly decreased serum T4 concentrations (P = .0024) compared to the control group. The concentration of type I collagen in the vocal folds of animals in the hypothyroid group was higher than in the control group (P = .0432), and an increase in the concentration of type III collagen was also observed (P = .0339). There was no statistically significant difference in the concentrations of elastin and hyaluronic acid between the groups.
Conclusion:
Hypothyroidism was able to cause changes in the extracellular matrix of the vocal folds of female rats. We found an increase in the concentration of type I collagen and type III collagen in the animals with hypothyroidism. There was no difference in the concentration of elastin and hyaluronic acid between the hypothyroid and control groups.
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