EXPRESSION AND CORRELATION BETWEEN DIFFERENT MOLECULES OF THE INNATE IMUNE SYSTEM, OSTEOCLASTOGENESIS AND METALOPROTEINASES IN THE GENESIS AND PROGRESSION OF PERIAPICAL LESIONS OF KNOCKOUT E WILD TYPE MICE

Abstract

Knowledge of the biological events occurring in the periapical tissue of teeth with pulp necrosis is crucial to understand the development of periapical lesions. Several molecules and mediators participate in the installation of the periapical lesion, since the bacterial infection that occurs inside the root canals. Thus, the aim of the present study will be evaluate the expression and interaction of different molecules of the innate immune system, osteoclastogenesis and metalloproteinases in experimentally periapical lesion (PL) induced in knockout and wild type mice. For this purpose, the present study will be divided into two distinct studies. The first study aim to evaluate the expression of metalloproteinases 2 (MMP2) and 9 (MMP9) during the progression of PL in TLR2 knockout mice (TLR2 KO) and MyD88 knockout mice (MyD88 KO), compared to wild type mice (WT). Periapical lesions will be induced in lower molars of 54 TLR2 KO, MyD88 KO and WT mice (n = 18/group). After 7, 21 and 42 days, the animals will be euthanized and the jaws dissected and submitted to histotechnical processing. Sections will be submitted to immunohistochemistry and the presence or absence of MMP2 and MMP9 in the different groups will be evaluated. The second study will evaluate the correlation of gene expression and immunostaining of RANK, RANKL, OPG, TLR2 and MyD88 during PL progression in WT mice (n = 35). Periapical lesions will be induced in the lower first molars on both sides of the jaw. After 0, 7, 21 and 42 days, the animals will be euthanized and the jaws dissected and divided in half. The right side of the jaws will be submitted to histotechnical processing for subsequent imunostaining of RANK, RANKL, OPG, TLR2 and MyD88. The left side of the jaws will used for the extraction of mRNA, for the expression evaluation of RANK (Tnfrsf11a), RANKL (Tnfrsf11), OPG (Tnfrsf11b), TLR2 (Tlr2) and MyD88 (Myd88) using qRT-PCR. For both studies, parametric and non-parametric tests will be performed with significance level of 5%. (AU)