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Updated: Jun 27, 2026
11:28
Analytical Techniques for Assaying Nitric Oxide Bioactivity
Published on: June 18, 2012
iNOS-derived nitric oxide modulates infection-stimulated bone loss
S Y Fukada1, T A Silva, I F Saconato
1Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes 3900, Monte Alegre, 14049-900, Ribeirão Preto SP, São Paulo, Brazil.
Journal of Dental Research
|November 26, 2008
Summary
Nitric oxide (NO) deficiency exacerbates bone loss in apical periodontitis. Inducible nitric oxide synthase knockout mice showed increased osteoclast activity and severe infection-induced bone destruction.
Area of Science:
- Immunology
- Oral Biology
- Pathology
Background:
- Inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) is crucial for host defense and managing inflammation.
- Apical periodontitis, a common dental infection, can lead to significant bone loss around the tooth root.
Purpose of the Study:
- To investigate the role of NO in bone loss during bacterial infection-induced apical periodontitis.
- To determine the impact of iNOS deficiency on inflammatory responses and bone resorption in this model.
Main Methods:
- Utilized iNOS-deficient (iNOS(-/-)) mice and wild-type (WT) littermates.
- Induced apical periodontitis through bacterial infection.
- Assessed inflammatory cell recruitment, osteolytic lesions, and osteoclastogenesis (TRAP+ cells).
- Quantified expression of key bone remodeling factors: RANK, SDF-1α/CXCL12, and OPG.
Main Results:
- iNOS(-/-) mice exhibited heightened inflammatory cell infiltration and more severe osteolytic lesions compared to WT mice.
- A significant increase in tartrate-resistant acid-phosphatase-positive (TRAP+) osteoclasts was observed in iNOS(-/-) mice.
- Bone resorption in iNOS(-/-) mice correlated with elevated RANK and SDF-1α/CXCL12 expression and reduced OPG levels.
Conclusions:
- NO derived from iNOS plays a protective role against infection-stimulated bone loss in apical periodontitis.
- NO deficiency leads to an imbalance in bone resorption regulators, promoting severe bone destruction.
- Targeting iNOS or NO pathways may offer therapeutic strategies for managing bone loss in apical periodontitis.
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