Analysis of senescence in gingival tissues and gingival fibroblast cultures.

Objective: To determine senescence-associated changes in the gingival tissues of aged mice and gingival fibroblast cultures.

Materials And Methods: The production of senescence-associated β-galactosidase (SA-β-gal) and mRNA expression of p16, p21, interleukin (IL)-1β, and tumor necrosis factor α (TNF-α) were evaluated in gingival tissues, gingival fibroblasts of 10- and 20-month-old C57BL/6NCrl mice, and multiple-passaged and hydrogen peroxide-stimulated human gingival fibroblasts (HGFs). Changes in molecular expression in HGF cultures due to senescent cell elimination by the senolytic drug ABT-263 (Navitoclax) were analyzed.

Results: Compared to 10-week-old mice, the 20-month-old mice had higher numbers of M1 macrophages. The proportion of cells expressing SA-β-gal were also higher in 20- month-old mice than in 10-week-old-mice. Gingival fibroblasts in 20-month-old mice expressed less collagen 1a1, collagen 4a1, and collagen 4a2 mRNA than those in 10-week-old mice. Compared to control cells, H2O2 treated HGF cells expressed higher levels of SA-β-gal and p16, p21, IL-1β, and TNF-α. Furthermore, ABT-263 suppressed HGF cell expression of cytokines after senescence induction.

Conclusions: Senescence-associated changes were observed in the gingival tissues of aged mice and HGF cultures. In addition, the potential of senolytic drugs to modify aging-related changes in the gingiva was shown.