The Stromal Cell-derived Factor-1 Expression Protected in Periodontal Tissues Damage during Occlusal Traumatism

Abstract

Mechanical stress (MS) during hyperocclusion results in elimination of the alveolar hard line, enhancement of bone resorption, and shedding of a tooth, resulting in trauma of occlusion. Several studies have indicated that MS induces cytokine and chemokine expression during alveolar bone absorption in periodontitis and orthodontic treatment. However, it remains unknown regarding the effect of hyperocclusal MS on maintenance of alveolar bone metabolism. Using in vivo and in vitro hyperocclusion models, we investigated the effect of MS on relationships between the expression of stress-dependent and osteoblastogenesis-associated chemokines. In the in vitro model with 6-weeks old mice, MS upregulated the expression of stromal cell-derived factor-1 (SDF-1) in periodontal tissues, a self-renewal chemokine in bone marrow stem cell day 4 after MS. In contrast, in the in vivo model with 30-weeks old mice, SDF-1 expression was significantly upregulated at day 1 after MS in periodontal tissues. MS induced the expression of SDF-1 in the PDL root branch and of the SDF-1 receptor CXCR4 in the dental pulp and bone marrow on day 4 in an in vivo mice model. MS upregulated the expression of SDF-1 in PDL cells. SDF-1 binds to CXCR4, resulting in MS-resistant alveolar bone protection during occlusal traumatism.