Oxidative stress caused by a low concentration of hydrogen peroxide induces senescence-like changes in mouse gingival fibroblasts

Periodontal tissue deteriorates under persistent oxidative stress induced by inflammatory reactions in the microflora of the oral cavity. This study aimed to evaluate the cellular properties of mouse gingival fibroblasts (MGFs) in the presence of oxidative stress. MGFs from 10-, 30- and 52-week-old mice were used to evaluate the changes in the cellular properties with aging. The study investigated the effects of oxidative stress on the cellular properties of MGFs from 10-week-old mice. The expression of p53, p21 and murine double minute 2 (Mdm2) in the MGFs in response to oxidative stress was also examined. By day 8, the number of MGFs increased in culture. However, the increase was markedly lower n MGFs derived from aged mice. Oxidative stress due to hydrogen peroxide (H2O2)-induced morphological changes characterized by a round shape with enlarged nuclei and expanded cytoplasm. The cell number of MGFs was decreased subsequent to treatment with 50 mu M or a higher concentration of H2O2. MGR treated with H2O2 at 20 mu M showed a similar cell growth curve as the one seen in 52-week-old mice. Phosphorylated p53 protein was increased in MGFs subsequent to treatment with 20 mu M H2O2, along with an upregulated transcription of p21 and Mdm2 mRNAs. These results suggest that treatment with a lower concentration of H2O2 in MGFs induces cell cycle arrest, resulting in stress-induced premature senescence, possibly correlated with the development of periodontal diseases.