Effect of the annexin a1 absence on the periodontium during the induction and resolution of experimental periodontitis and on bone repair in mice: microtomographic, immunoenzymatic, and microbiological evaluation

• Grant number: 23/16938-0
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2025
• End date: January 31, 2027
• Field of knowledge: Health Sciences - Dentistry - Periodontology
• Principal Investigator: Mabelle de Freitas Monteiro
• Grantee: Mabelle de Freitas Monteiro
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Associated researchers: Mônica Grazieli Corrêa ; Renato Corrêa Viana Casarin ; Suzana Peres Pimentel

Abstract

Periodontal disease is a multifactorial inflammatory disease. Thus, alterations in the inflammatory profile and the expression of some host response regulatory molecules could favor the development of periodontal disease and interfere with periodontal and bone repair. A recent study from our research group suggested Annexin A1 (AnxA1), a pro-resolving inflammatory molecule, as a potential salivary biomarker for susceptibility to periodontics. However, there are no studies evaluating the influence of this molecule in periodontics. This project aims to 1) study the influence of AnxA1 on the development of periodontal disease and its effect on the resolution of the periodontal lesion, evaluating the pattern of bone loss, and the local expression of bone and inflammatory markers; 2) its effect on the periodontal microbiome in mice; 3) to evaluate the effect of AnxA1 on bone repair. Forty C57BL/6 mice, 20 of them AnxA1 knockouts (test group - AnxA1/) and 20 with a regular expression (control group -WT), will be included in the study. Initially, 10 test mice and ten controls will undergo surgery to perform a critical bilateral calvaria defect with a trephine. Additionally, these same animals will be submitted to induction of experimental periodontitis by ligature for ten days. After this period, they will be euthanized for analysis. In addition, another 10 test mice and 10 controls will receive ligature for 10 days, the ligature will be removed, and they will be euthanized after 5 days to assess the importance of AnxA1 in the resolution of inflammation. After euthanasia, the mandible will be used to evaluate periodontal bone loss by Micro-Ct and to evaluate bone markers using immunohistochemistry, while the gingival tissue will be collected for immunoenzymatic evaluation of pro- and anti-inflammatory cytokines using Luminex/MAGpix. For microbiological evaluation, 20 mice will undergo the cycle of induction and resolution of periodontitis (10 in the test group and 10 in the control group). Bacterial samples will be collected in three timepoints: T0) before the placement of the ligature, T1) 10 days after the placement of the ligature, and T2) 5 days after the removal of the ligature. Bacterial DNA will be extracted and sequenced with the Illumina Miseq platform, and the microbiome will be analyzed with bioinformatics tools. All analyses will be performed using an ±=5%. (AU)