Gingivitis in Mice and the Role of Angiogenesis

Abstract Background Gingivitis is the first step in an abnormal oral condition, which degrades connective tissue and eventually converts to periodontal diseases leading to alveolar bone and tooth loss. Thrombospondin-1 (TSP1) and Bcl-2 are key regulators of angiogenesis. The transition from gingivitis into periodontitis has four stages and disease progression depends very heavily on changes to the surrounding vasculature structures. We hypothesized that vascular dysfunction plays an important role in the progression of gingivitis. Here we have measured Gingival Crevicular Fluid (GCF) levels in TSP1 and Bcl-2-deficient mice, in which vascular structures are affected, while also looking at the roles that age and gender play in this process. Methods Thirty mice (15 males and 15 females) were divided into three groups of ten (n=10): group A (WT), group B (TSP1 -/-), and group C (Bcl-2 -/-) were subjected to collection of Gingival Crevicular Fluid (GCF). Saliva was collected from different groups of mice after subcutaneous injection of pilocarpine. For the WT group, GCF was monitored for 3, 4, 5 and 6 weeks and the contribution of age was also considered. RESULTS: Samples from Bcl-2 -/- mice showed significantly lower levels of GCF and salivary secretions, while TSP1-/- mice were larger and secreted more saliva. Moreover, the TSP1-/- mice GCF level was significantly higher than that of both the WT and Bcl-2 -/- mice. CONCLUSIONS: The absence of Bcl-2 and TSP1 significantly affects the amount of GCF flow in mice. This current study confirms the important role that alteration of pro- and anti-angiogenic factors can play in the progression of gingivitis and in the amount of salivary secretions. Thus, this type of modulation of angiogenic proteins provides a great opportunity and a novel platform for developing enhanced oral care products of the future. TSP1 showed significantly more saliva secretion, and a larger volume of periodontal pocket. This means that higher level saliva secretion can affect periodontal pocket volume and eventually oral hygiene.