Archives of oral biology | 2019
A study of chewing muscles: Age-related changes in type I collagen and matrix metalloproteinase-2 expression.
Abstract
OBJECTIVE\nIn this study, the aim was to investigate the biochemical, physiological and histological changes that occur in masticatory muscles of the masticatory system with aging.\n\n\nDESIGN\nIn this study, 14 BALB/c mice were used. Animals were divided into two equal groups of seven. Group I was organized as the group of young animals (n\u202f=\u202f7) and Group II as the group of adult animals (n\u202f=\u202f7). After routine histological follow-up was performed, the tissues were embedded in paraffin. 4-5\u202fμm thick cross-sections were taken from paraffin-embedded tissues and they were stained with Haemotoxylin and Eosin Type I collagen and Matrix metalloproteinase-2 (MMP-2) immunohistochemically.\n\n\nRESULTS\nIt was observed that there was a decrease and shrinking in blood vessels due to aging. In young mice, Type I collagen and MMP-2 immunoreactivity in the masseter muscle tissue showed low staining, while Type I collagen and MMP-2 immunoreactivity in the temporal muscle tissue showed moderate staining. Type I collagen and MMP-2 immunoreactivity were significantly higher in the masseter and temporal muscles of elderly mice (p\u202f=\u202f0.001). In the H-score evaluation, MMP-2 immune reactivity was significantly lower in young mice than in older mice (p\u202f=\u202f0.001).\n\n\nCONCLUSION\nIt was determined that severe pain complications and functional losses are likely to occur with the increase of degeneration due to aging of masticator muscles.