Age-related differences in the expression of heat shock protein 27 by rat periodontal ligament cells in culture

Abstract

To evaluate age-related differences in the expression of heat shock protein (HSP) 27 in periodontal ligament (PDL) cells at the protein and mRNA levels, we obtained PDL cells from the incisors of rats weighing approximately 150 g (young group) and 350 g (aged group) and seeded the cells in culture dishes. Over 2 weeks of cultivation, PDL cells were subjected to quantitative reverse transcription polymerase chain reaction (RT-PCR) to measure HSP27 mRNA, and HSP27 protein expression was examined by immunofluorescence. HSP27 mRNA expression in the young group increased slightly over the 2 weeks, while in the aged group it increased significantly over the same time period. The expression ratio of HSP27 mRNA in the aged group was higher than in the young group at 14 days. Furthermore, immunofluorescence signals for HSP27 were stronger in the aged group than in the young group. These data reveal that PDL cells vary their expression of HSP27 with age, and suggest that in view of such changes in HSP27 mRNA expression, the self-defense mechanism is enhanced in aged PDL cells although their overall homeostatic conditions are suppressed.

Regenerative capability of dental pulp cells after crown fracture

“…Heat shock protein 27 is a protective protein for cells, serves as a molecular chaperone in maintaining homeostasis, and is expressed physiologically in response to stress (18). VEGF is an angiogenic growth factor that elicits cellular responses to injury (19).…”