Increased oxygen exposure alters collagen expression and tissue architecture during ligature-induced periodontitis

Background and Objective: The aim of this study was to evaluate the effects of increased oxygen availability on gene expression and on collagen deposition/maturation in the periodontium following disease. Material and Methods: Male Wistar rats had ligatures placed around their molars to induce periodontal disease, and a subset of animals underwent hyperbaric oxygen (HBO) treatment for 2 h twice per day. At 15 and 28 d, tissue gene expression of COL1A1, transforming growth factor-β1 and alkaline phosphatase was determined; other histological samples were stained with Picrosirius red to evaluate levels of collagen deposition, maturation and thickness. Results: In animals that underwent HBO treatment, type I collagen expression was higher and collagen deposition, maturation and thickness were more robust. Reduced mRNA levels of transforming growth factor-beta1 and alkaline phosphatase in HBO-treated rats on day 28 suggested that a quicker resolution in both soft tissue and bone remodeling occurred following oxygen treatment. No differences in inflammation were observed between groups. Conclusions: The extracellular matrix regenerated more quickly in the HBO-treated group as evidenced by higher collagen expression, deposition and maturation.