Role of AT1 and AT2 receptors in osteogenic differentiation in rats periodontal ligament cells

Abstract

The periodontal ligament is a soft tissue located between the cementum and the alveolar bone, which acts on bone remodeling and orthodontic tooth movement. Some cells in this tissue are capable of self-renewal and differentiation into multiple lineages, which are called periodontal ligament stem cells. Such cells have already demonstrated a strong ability to form structures similar to cementum, bone tissue, new periodontal ligaments, among others. There is evidence of a local renin angiotensin system (RAS) in this tissue and its influence on inflammation and bone metabolism. Thus, the objective of the project will be to evaluate the role of angiotensin II receptors type 1 (AT1) and 2 (AT2) during the in vitro osteogenic differentiation of periodontal ligament stem cells from Wistar rats. Therefore, the periodontal ligament of the animals' incisor teeth will be extracted, and culture up to passage 2. Cells will be differentiated towards osteoblastic lineage along with angiotensin stimulus, in the presence or absence of AT1R and AT2R antagonists, in order to observe the direct effect of angiotensin in the activation of the receptor for the osteogenic differentiation of these cells. This differentiation will be evaluated by cell proliferation, total protein content, alkaline phosphatase and biological mineralization. In addition, we will evaluate the gene expression of bone formation markers, and the angiotensin II receptors (AT1 and 2) by real-time RT-PCR and the production of TNF-± and IL-6 by ELISA. Possibly, with these studies, new discoveries will be obtained to contribute to the improvement of the situation of patients with severe oral inflammation as periodontal disease and periapical lesion where we also observe bone loss.