Age-related Changes in Rat Tongue

Abstract

The effects of ageing on the oral mucosa are believed to be relatively small. The purpose of this study was to identify morphological changes observed in rat tongue during ageing in 20-day-old, 3-month-old, 12-month-old, 28-month-old, and 48-month-old rats. Age-related changes in the thickness of the epithelium and lamina propria, the density of the elastic fibres and the number of mast cells were histomorphometrically analyzed. In 20-day-old rats, the stratified squamous epithelium and lamina propria thicknesses were thinnest, whereas with age, epithelial thickness reached its greatest thickness in 48-month-old rats and lamina propria thickness was most noticeable in 12-month-old rats. The arrangement and distribution of elastic fibres were disrupted in the lamina propria with ageing. The density of elastic fibres in lamina propria was lowest in 20-day-old rats, while in 12-month-old rats they reached their highest density, and then decreased sharply again in older rats. The number of mast cells per unit area was lowest in 20-day-old rats, reaching its highest number in 12-month-old rats and remaining high in older animals. In conclusion, with age, there was a moderate positive correlation and a statistically significant increase in tongue epithelial thickness, as well as a significant thickening of the lamina propria and an increase in the number of mast cells. The density of the elastic fibres in lamina propria decreased, but no negative correlation was observed with ageing.