IADR Abstract Archives
Cellular senescence may stimulate IL-6 in aged gingival wounds.
Objectives: Aging is characterized by increased levels of cellular senescence, a biological response in which senescent cells modify their transcriptional program, increasing the expression of inflammatory mediators that may modify tissue regeneration. In this study we have analyzed whether gingival fibroblasts derived from human aged subjects or induced to senescence by oxidative stress, may alter the expression of inflammatory factors of importance to the wound healing response.
Methods: Primary cultures of human gingival fibroblasts were obtained from young (n=4) and aged donors (n=4). Gingival fibroblasts were exposed to hydrogen peroxide to induce senescence. Cellular senescence was assessed by identifying cell size and by staining for gamma H2A.x and Senescence Associated beta galactosidase. Cell proliferation was assessed by immunofluorescence for Ki67. The expression of senescence-associated genes was evaluated by RT-qPCR. Gingival wounds were performed in young and aged mice to evaluate the expression of IL-6 using immunohistochemistry. Statistical analysis was performed by using the unpaired t test or Mann-Whitney test through Prism.
Results: Among different mediators evaluated, gingival fibroblasts from aged donors secreted significantly increased amounts of IL-6 at the protein levels and showed augmented levels of senescence when compared to young counterparts. Gingival fibroblasts stimulated with H2O2 became senescent and showed significantly increased IL-6 expression levels. Gingival wounds in aged mice showed signs of delayed connective tissue healing and increased IL-6 levels when compared to young wounds.
Conclusions: The present results suggest that aged wounds are characterized by increased levels of IL-6 and cellular senescence may stimulate IL-6 secretion in gingival fibroblasts. This mechanism may contribute to the pathogenesis found in delayed aged gingival wounds.
Methods: Primary cultures of human gingival fibroblasts were obtained from young (n=4) and aged donors (n=4). Gingival fibroblasts were exposed to hydrogen peroxide to induce senescence. Cellular senescence was assessed by identifying cell size and by staining for gamma H2A.x and Senescence Associated beta galactosidase. Cell proliferation was assessed by immunofluorescence for Ki67. The expression of senescence-associated genes was evaluated by RT-qPCR. Gingival wounds were performed in young and aged mice to evaluate the expression of IL-6 using immunohistochemistry. Statistical analysis was performed by using the unpaired t test or Mann-Whitney test through Prism.
Results: Among different mediators evaluated, gingival fibroblasts from aged donors secreted significantly increased amounts of IL-6 at the protein levels and showed augmented levels of senescence when compared to young counterparts. Gingival fibroblasts stimulated with H2O2 became senescent and showed significantly increased IL-6 expression levels. Gingival wounds in aged mice showed signs of delayed connective tissue healing and increased IL-6 levels when compared to young wounds.
Conclusions: The present results suggest that aged wounds are characterized by increased levels of IL-6 and cellular senescence may stimulate IL-6 secretion in gingival fibroblasts. This mechanism may contribute to the pathogenesis found in delayed aged gingival wounds.