acid-phosphatase and Periapical-Periodontitis

Enterococcus faecalis is considered a major bacterial pathogen implicated in endodontic infections and contributes considerably to periapical periodontitis. This study aimed to investigate the potential mechanisms by which E. faecalis accounts for the bone destruction in periapical periodontitis in vitro. Osteoclast precursor RAW264.7 cells were treated with E. faecalis ATCC 29212 and a wild strain of E. faecalis derived clinically from an infected root canal. The results showed that, to some extent, E. faecalis induced the RAW264.7 cells to form tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclast-like cells. This pathogen markedly stimulated RAW264.7 cells to express semaphorin 4D (Sema4D), which inhibits bone formation. Once RAW264.7 cells were primed by low-dose receptor activator of nuclear factor-kappa B ligand (RANKL), E. faecalis could significantly increase the production of TRAP-positive multinucleated cells and up-regulate the expression of osteoclast-specific markers, including NFATc1, TRAP and cathepsin K. Both p38 and ERK1/2 MAPK signaling pathways were activated by E. faecalis in RANKL-primed RAW264.7 cells, and meanwhile the expression of Sema4D was highly increased. In conclusion, E. faecalis may greatly contribute to the bone resorption in periapical periodontitis by promoting RANKL-dependent osteoclastogenesis and expression of Sema4D through activation of p38 and ERK1/2 MAPK signaling pathways.

Topics: Acid Phosphatase; Animals; Antigens, CD; Bone Resorption; Cell Differentiation; Cell Line; Enterococcus faecalis; Gene Expression Regulation; Gram-Positive Bacterial Infections; Humans; Isoenzymes; Mice; Mitogen-Activated Protein Kinase Kinases; NFATC Transcription Factors; Osteoclasts; Periapical Periodontitis; RANK Ligand; Semaphorins; Signal Transduction; Tartrate-Resistant Acid Phosphatase; Transcriptome

Apical periodontitis is an inflammation and destruction of periapical tissues. Matrix metalloproteinase-9 (MMP-9) is thought to be involved in periapical lesion formation and progression. The aim of this study was to evaluate the lesion progression in MMP-9 knockout (KO) mice compared with that in control mice (wild type [WT]).. The pulps of mouse mandibular first molars were exposed; animals were killed at 0, 7, 14, 21, and 28 days after surgery. Hematoxylin-eosin-stained sections were observed for the description of pulpal, apical, periapical features, and the periapical lesion size. The periapical lesion size was further measured with micro-computed tomographic imaging. The number of osteoclasts was also counted by tartrate-resistant acid phosphatase histoenzymology. Real-time polymerase chain reaction and immunohistochemistry were used to analyze the expression levels of receptor activator of NF-κB (RANK), receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), MMP-2, and MMP-8.. There was a significant difference (P < .05) between the 2 types of animals regarding the periapical lesion size, which was larger in MMP-9 KO animals. No significant differences (P > .05) were found between WT and MMP-9 KO mice related to the osteoclast number as well as the pulpal, apical, and periapical features. More neutrophil cells were observed in MMP-9 KO animals than WT mice (P < .05). The expression levels of RANK, RANKL, OPG, IL-1β, TNF-α, MMP-2, and MMP-8 were found up-regulated in MMP-9 KO mice (P < .05).. MMP-9 KO animals developed larger periapical lesions with greater inflammatory response, indicating an important role of MMP-9 in the host's immune and inflammatory response to root canal and periradicular infection.

Topics: Acid Phosphatase; Animals; Cell Count; Dental Pulp Exposure; Disease Progression; Interleukin-1beta; Isoenzymes; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 8; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Neutrophils; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha; X-Ray Microtomography

The purpose of this study was to evaluate the expression of Dickkopf-1 (DKK-1), a secreted antagonist of the Wnt (wingless)/beta-catenin signaling pathway, during the development of periapical lesions in rats.. Periapical lesions were induced in Wistar rats by occlusal exposure of the pulp of their mandibular first molars. The animals were sacrificed randomly at 0, 7, 14, 21, and 28 day after pulpal exposure. Jaws containing the first molar were obtained and routinely prepared for histologic, immunohistochemical, and enzyme histochemical double immunofluorescence analyses. Data were analyzed using 1-way analysis of variance and Pearson correlation test.. The expansion of the area of periapical lesions was visible from days 7-21 and slowed down thereafter. A few DKK-1- and receptor activator of nuclear factor kappa B ligand (RANKL)-positive cells and osteoclasts were observed on day 7. All positive samples peaked in number on day 14. The expression levels of DKK-1 and RANKL and the number of osteoclasts decreased on days 21 and 28. DKK-1 expression was positively correlated with RANKL expression and osteoclast number from days 7-28.. DKK-1 expression was up-regulated during periapical lesion development. DKK-1 may be associated with the inflammatory response and bone resorption in periapical lesions.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; Biomarkers; Cell Count; Dental Pulp Exposure; Image Processing, Computer-Assisted; Intercellular Signaling Peptides and Proteins; Isoenzymes; Male; Osteoclasts; Periapical Periodontitis; Periapical Tissue; Random Allocation; RANK Ligand; Rats; Rats, Wistar; Tartrate-Resistant Acid Phosphatase; Time Factors

Nitric oxide (NO) and reactive oxygen species (ROS) are key molecules in resistance to pathogens. Little is known about their role in pathogenesis of periapical lesions. To address this issue, we induced periapical lesions in mice lacking nitric oxide synthase (iNOS(-/-)) or phagocyte oxidase (PHOX(-/-)). iNOS(-/-) mice expressed higher levels of IL-1β, TNF-α, RANK, RANKL, and MCP-1 than C57BL/6 and PHOX(-/-). Apical thickening of the periodontal ligament was also greater in iNOS(-/-) compared with other groups. Interestingly, ROS production did not interfere in periapical lesion progression, but seemed to be essential for the appearance of multinucleated TRAP-positive cells. Thus, periapical lesion progression in iNOS(-/-) was associated with an imbalance of pro-inflammatory cytokines (IL-1β and TNF-α), bone-resorptive modulators (RANK and RANKL), and MCP-1. We conclude that NO, but not ROS, controls progression of bone resorption in a murine experimental model of apical periodontitis.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; Biomarkers; Chemokine CCL2; Cytokines; Disease Models, Animal; Disease Progression; Inflammation Mediators; Interleukin-1beta; Isoenzymes; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Mice, Knockout; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase Type II; Periapical Periodontitis; Periodontal Ligament; Phagocytes; RANK Ligand; Reactive Oxygen Species; Receptor Activator of Nuclear Factor-kappa B; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha

Alveolar bone destruction is associated with enhanced osteoclast activity; tumor necrosis factor receptor-associated factor 6 (TRAF6) is suggested to contribute to the differentiation of osteoclasts. The purpose of this study was to observe the immunohistochemical localization of TRAF6 and bone resorption in induced periapical lesions in rats.. Periapical lesions were induced by an occlusal pulp exposure in the mandibular first molars. Animals were randomly killed at 0, 7, 14, 21, and 28 days. Frontal sections were prepared for immunohistochemistry and enzyme histochemistry.. A few TRAF6-positive cells and osteoclasts could be observed on day 7. Both climaxed on day 14. In the 21-day and 28-day samples, TRAF6 expression decreased, and fewer osteoclasts were observed. From day 7 to day 28, a significant positive correlation was found between TRAF6 expression and osteoclast numbers.. These findings showed that TRAF6 might be associated with osteoclast differentiation in periapical lesions.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; Cell Count; Cell Differentiation; Female; Immunoenzyme Techniques; Isoenzymes; Osteoclasts; Periapical Periodontitis; Rats; Rats, Wistar; Second Messenger Systems; Tartrate-Resistant Acid Phosphatase; TNF Receptor-Associated Factor 6

The purpose of this study was to investigate the activation of p38 mitogen-activated protein kinase (MAPK) during the development of periapical lesions in rats. Periapical lesions developed within 28 days after pulp exposure of mandibular first molars in Wistar rats. The animals were sacrificed randomly at 0, 7, 14, 21, and 28 days after pulpal exposure. The jaws that contained the first molar were obtained and routinely prepared for immunohistochemistry and enzyme histochemistry. A few phosphorylated p38 MAPK (P-p38)-positive cells and osteoclasts could be observed on day 7; both peaked in number on day 14. In the 21- and 28-day samples, the P-p38 MAPK expression decreased and fewer osteoclasts were observed. From day 7 to day 28, a significant positive correlation was found between P-p38 MAPK expression and osteoclasts. These findings showed that the activation of p38 MAPK might be associated with bone resorption in periapical lesions.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; Biomarkers; Cell Count; Cell Nucleus; Coloring Agents; Dental Pulp Exposure; Enzyme Activation; Immunohistochemistry; Isoenzymes; Male; Mandibular Diseases; Osteoclasts; p38 Mitogen-Activated Protein Kinases; Periapical Diseases; Periapical Periodontitis; Random Allocation; Rats; Rats, Wistar; Tartrate-Resistant Acid Phosphatase

Nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) plays an important role in host defense, as well as in inflammation-induced tissue lesions. Here we evaluated the role of NO in bone loss in bacterial infection-induced apical periodontitis by using iNOS-deficient mice (iNOS(-/-)). The iNOS(-/-) mice developed greater inflammatory cell recruitment and osteolytic lesions than WT mice. Moreover, tartrate-resistant acid-phosphatase-positive (TRAP(+)) osteoclasts were significantly more numerous in iNOS(-/-) mice. Furthermore, the increased bone resorption in iNOS(-/-) mice also correlated with the increased expression of receptor activator NF-kappaB (RANK), stromal-cell-derived factor-1 alpha (SDF-1 alpha/CXCL12), and reduced expression of osteoprotegerin (OPG). These results show that NO deficiency was associated with an imbalance of bone-resorption-modulating factors, leading to severe infection-stimulated bone loss.

Topics: Acid Phosphatase; Actinomycosis; Alveolar Bone Loss; Animals; Bacterial Infections; Bacteroidaceae Infections; Biomarkers; Cell Count; Cell Movement; Chemokine CXCL12; Dental Pulp Exposure; Isoenzymes; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Nitric Oxide; Nitric Oxide Synthase Type II; Osteoclasts; Osteolysis; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Tartrate-Resistant Acid Phosphatase

The object of this study was to elucidate the kinetics of receptor activator of NFkB ligand (RANKL), RANK, osteoprotegerin (OPG), and cytokine expressions in experimentally induced rat periapical lesions.. The mRNA expressions of RANKL, RANK, OPG, and cytokines in experimentally induced rat periapical lesions were evaluated by real-time PCR. The lesions were induced in male Wistar rats (n = 48, 5 weeks of age) by unsealed pulp exposure of the lower first molars.. Expression of RANKL was up-regulated at the beginning of lesion expansion, and expression ratio of RANKL against OPG, a competitor of RANKL, peaked at 2 and 3 weeks. Expression of inflammatory cytokines, such as TNF-alpha, IL-1alpha, and IL-1beta also increased at this stage, suggesting contribution of synergic effects of RANKL and proinflammatory cytokine signaling to lesion expansion. Most of RANKL+ cells were fibroblastic, but few of them were T cells.. Expression of RANKL and proinflammatory cytokines was correlated with periapical lesion expansion.

Topics: Acid Phosphatase; Animals; Cytokines; Immunoenzyme Techniques; Interleukin-10; Interleukin-1alpha; Interleukin-1beta; Isoenzymes; Kinetics; Male; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Rats; Rats, Wistar; Receptor Activator of Nuclear Factor-kappa B; Receptors, Antigen, T-Cell, alpha-beta; Reverse Transcriptase Polymerase Chain Reaction; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha

Cells expressing interleukin-1 beta (IL-1 beta) mRNA were demonstrated by in situ hybridization in rat periapical lesions. A great number of osteoclasts with significant tartrate-resistant acid phosphatase activity were observed on the bone surfaces, and numerous IL-1 beta mRNA-expressing cells were widely distributed in the periodontal ligaments. IL-1 beta mRNA-expressing cells were mainly observed around the blood vessels in the vicinity of the bone resorption sites and occasionally found near the osteoblasts. Immunohistochemistry and enzyme histochemistry assays showed that IL-1 beta mRNA-expressing cells were not bone cells, but that they had the characteristic features of macrophages. These results suggested that macrophages may contribute to the production of IL-1 beta and play an important role in activation of osteoclastic bone resorption.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; CD40 Ligand; Immunoenzyme Techniques; In Situ Hybridization; Interleukin-1; Isoenzymes; Macrophages; Membrane Glycoproteins; Oligonucleotide Probes; Osteoclasts; Periapical Periodontitis; Periodontal Ligament; Rats; Rats, Wistar; RNA, Messenger; Tartrate-Resistant Acid Phosphatase

Bone alkaline and tartrate-resistant acid phosphatase activities were studied in paraffin sections obtained from experimentally induced periapical lesions of rats. These enzyme activities were demonstrated despite the use of high temperatures during embedding. In the formation phase, numerous osteoblasts and periodontal ligament cells showed strong alkaline phosphatase activity. On the other hand, a number of osteoclasts and preosteoclasts showed tartrate-resistant acid phosphatase activity in the activated resorption sites of periapical lesions. It is suggested that enzyme histochemical applications to paraffin sections are a useful means for clarifying the behavior of bone cells and that bone remodeling has occurred in the periapical lesions.

Topics: Acid Phosphatase; Alkaline Phosphatase; Alveolar Bone Loss; Animals; Bone Remodeling; Histocytochemistry; Osteoblasts; Osteoclasts; Paraffin Embedding; Periapical Periodontitis; Periodontal Ligament; Rats; Rats, Wistar; Tartrates; Time Factors

An apical periodontitis experimental model was produced by means of opening the pulp chamber of the mandibular first molar in Wistar strain rats. In particular, the behavior of bone tissue in the vicinity of the root apex was investigated histochemically, ultrastructurally, and quantitatively. In addition, in order to demonstrate the effects of prostaglandin on the formation process of apical periodontitis, we examined the effects of indomethacin on bone remodeling during experimental apical periodontitis. These experiments suggested that prostaglandin may stimulate osteoclastic bone resorption and that the relationship between bone resorption and formation in apical periodontitis is a coupling phenomenon.

Topics: Acid Phosphatase; Animals; Bone Regeneration; Bone Remodeling; Bone Resorption; Female; Histocytochemistry; Indomethacin; Osteoblasts; Osteoclasts; Periapical Periodontitis; Prostaglandin Antagonists; Prostaglandins; Rats; Rats, Inbred Strains; Staining and Labeling; Time Factors