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In vivo Imaging Method to Distinguish Acute and Chronic Inflammation
Published on: August 16, 2013
The role of iNOS and PHOX in periapical bone resorption
M J B Silva1, L M A Sousa, V P L Lara
1Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, CP 486, 30161-970 Belo Horizonte, MG, Brazil.
Abstract:
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.
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