Histological characterization of rat vocal fold across different postnatal periods

Abstract Objective To evaluate the vocal fold histological characteristics during different postnatal periods in rats, especially older rats. Methods Sprague–Dawley rats aged 4 days, 4 and 12 weeks, and 12 and 24 months were used for the experiment. Five larynges were obtained for each age and cut into 5‐μm consecutive sections. The expression of Ki‐67 was assessed using immunohistochemistry to examine cell proliferation. Elastic van Gieson staining was used to detect the collagen and elastin concentrations. The cell type was determined using multicolor immunofluorescence. Results Ki‐67 was not expressed in the macula flava (MF) of 12‐week‐, 12‐month‐, and 24‐month‐old adults. Collagen fibers in the lamina propria (LP) increased with age. The elastic fiber concentrations in the LP decreased significantly at 24 months (p