Effect of methotrexate-induced neutropenia on rat periapical lesion

Interferon-gamma, Interleukin-10, Intercellular Adhesion Molecule-1, and Chemokine Receptor 5, but not Interleukin-4, Attenuate the Development of Periapical Lesions

“…In addition, the degranulation of neutrophils could be implicated in connective tissue destruction. In rats, the methotrexate-induced neutropenia elicited after pulpal exposure did not change the status of the periapical lesion, whereas the neutropenia before the exposure inhibited the infiltration of inflammatory cells, especially that by neutrophils, into the lesion and the development of the periapical lesion (25). This finding suggests that neutrophils infiltrated in periapical tissue initiate the development of the periapical lesion.…”

Role of IL-2 and Helper T-Lymphocytes in Limiting Periapical Pathosis

“…These lymphocytes were the predominant inflammatory cells that infiltrated in human periradicular lesions (11,12). The periradicular lesions induced by pulpal exposure in rats is a well-established model and very useful to investigate the developmental process of such lesions (20,21). In this study, we investigated the histological changes during pulpal and periapical inflammation including necrosis, abscess formation, alveolar bone resorption, and root resorption.…”

“…All animals were anesthetized with diethyl ether, and then the pulpal tissue in the left mandibular first molar was exposed with a #1/2 round bar to a depth equal to the diameter of the bar, so that furcal perforation would be avoided. The exposed tooth was left open to the oral environment throughout the experiment (20,21).…”

“…We chose sections that included the site of pulp exposure and the root canal foramen, and the sections were therefore made in the central portion of the periradicular lesions. The areas of pulpal necrosis, apical abscess, and periradicular lesion were measured histometrically as described previously (20,21). The area of pulpal necrosis was that with no cellular tissue in the root canal under the furcation of the root, the area of apical abscess was the abscess adjacent to the root apex, and the area of the periradicular lesion was the periodontal ligament between the root apex and the alveolar bone in the mesial root.…”

High Matrix Metalloproteinase Activity Is a Hallmark of Periapical Granulomas

“…The role of PMNs in periapical disease pathogenesis is well-established (36). Differential expression of MMP-9 in PMNs from granulomas compared to cysts represents an interesting finding, since PMNs uniquely regulate MMP expression.…”