Matrix Metalloproteinase-1 and Acid Phosphatase in the Degradation of the Lamina Propria of Eruptive Pathway of Rat Molars

Abstract

The comprehension of dental pathogenesis and disorders derived from eruption failure requires a deep understanding of the molecular mechanisms underlying normal tooth eruption. As intense remodelling is needed during tooth eruption, we hypothesize that matrix metalloproteinase-1 (MMP-1) and acid phosphatase (ACP) play a role in the eruptive pathway degradation. We evaluated MMP-1-immunoexpression and the collagen content in the lamina propria at different eruptive phases. Immunohistochemistry and ultrastructural cytochemistry for detection of ACP were also performed. In the maxillary sections containing first molars of 9-, 11-, 13-, and 16-day-old rats, the birefringent collagen of eruptive pathway was quantified. MMP-1 and ACP-2 immunohistochemical reactions were performed and the number of MMP-1-immunolabelled cells was computed. Data were analyzed by one-way ANOVA and Tukey post-test (p ≤ 0.05). ACP cytochemistry was evaluated in specimens incubated in sodium β-glycerophosphate. In the eruptive pathway of 13- and 16-day-old rats, the number of MMP-1-immunolabelled cells increased concomitantly to reduction of collagen in the lamina propria. Enhanced ACP-2-immunolabelling was observed in the lamina propria of 13- and 16-day-old rats. Fibroblasts and macrophages showed lysosomes and vacuoles containing fragmented material reactive to ACP. MMP-1 degrades extracellular matrix, including collagen fibers, being responsible for the reduction in the collagen content during tooth eruption. The enhanced ACP activity at the mucosal penetration stage indicates that this enzyme plays a role in the degradation of remnant material, which is engulfed by macrophages and fibroblasts of the eruptive pathway. Therefore, enzymatic failure in the eruptive pathway may disturbs tooth eruption.

Biocompatibility and bioactive potential of the NeoMTA Plus endodontic bioceramic-based sealer

“…This analysis was performed in 3 sections from each specimen, with a minimal distance of 100 µm between the sections. The polarized images were captured at ×40 magnification with rigorously standardized parameters (light intensity, diaphragm aperture, condenser position and exposition time) and the birefringent material ( i.e., collagen) was estimated as previously described [ 21 ]. The hue definition considered in the birefringence was as follows: red/orange, 2–38 and 230–256; yellow, 39–51; and green, 52–128.…”

“…The hue definition considered in the birefringence was as follows: red/orange, 2–38 and 230–256; yellow, 39–51; and green, 52–128. The amount of collagen was represented by the percentage of birefringent areas of the total area (expressed in pixels) calculated by ImageJ ® analysis software [ 21 22 23 ].…”

Role of Innate Inflammation in the Regulation of Tissue Remodeling during Tooth Eruption

“…MMP expression has been reported in the degradation of the lamina propria of the eruptive pathway of rat molar tooth [ 32 , 33 ]. Neutrophils and macrophages synthesize MMPs in response to proinflammatory cytokines [ 34 , 35 ].…”

Histomorphometric and immunohistochemical study shows that tricalcium silicate cement associated with zirconium oxide or niobium oxide is a promising material in the periodontal tissue repair of rat molars with perforated pulp chamber floors

“…The amount of collagen was calculated from the percentage occupied by birefringent material in each field. The content of collagen fibres (in percentage) was measured in the periodontal space in the furcation region of first molars using sections stained with 0.1% picrosirius-red and analysed under polarized light (de Pizzol-J unior et al 2018, da Fonseca et al 2019. Three non-serial sections, with minimal interval of 100 µm, were used of each specimen.…”

“…These images were analysed using the ImageJ software (ImageJâ, http://rsbweb.nih.gov/ij), considering the hues red/orange (2-38), yellow (230-256) and green (52-128) as birefringent collagen (de Pizzol-J unior et al 2018). Thus, the programme provided the amount of birefringent content (expressed in percentage) from the total number of pixels following a methodology previously described (Silva et al 2017a, de Pizzol-J unior et al 2018, da Fonseca et al 2019. shows a general view of a healthy molar of control group.…”