Immunolocalization of matrix metalloproteinases-2 and -9 during apical periodontitis development
Received 22 January 2009; received in revised form 15 April 2009; accepted 17 April 2009.
Abstract
Objective
The objective of this study was to determine the expression of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) during apical periodontitis development.
Methods
Using an experimental design of induced periapical lesions in rats and immunohistochemistry assay as investigative tool, the MMP-2 and MMP-9 expression and distribution were evaluated at 3, 7, 14, 21, 30, 60 and 90 days after coronary access and pulp exposure of the first left mandibular molar to the oral environment. Two blind observers scored the immunoreactivity. A semi-quantitative analysis was performed.
Results
Except at day 3, MMP-2 and MMP-9 immunostaining was observed in all experimental periods. The MMP-2 (p=0.004) and MMP-9 (p=0.005) immunostaining was higher in the period between 7 and 21 days. They were mainly observed in cells surrounding the apical foramen and adjacent periapical areas. Cells into the hypercementosis areas were strongly stained while both osteoblasts and osteoclasts presented discrete staining along of this study. No staining was observed on epithelial walls. At 30, 60 and 90 days, the subjacent connective tissue presented intense MMP-2 and MMP-9 immunostaining in mononuclear cells (suggestive of fibroblasts, macrophages, infiltrating neutrophils and lymphocytes).
Conclusion
The results observed in this study suggest that MMP-2 and MMP-9 play a critical role in the development of inflammatory periapical lesions, probably involved in the extracellular matrix (ECM) degradation during the initial phase of the lesion development.
aLaboratory of Biochemistry, Department of Biological Sciences, University of Sao Paulo, Bauru-SP, Brazil
bLaboratory of Bioassays and Signal Transduction; Department of Biochemistry, Institute of Biology, University of Campinas, Campinas-SP, Brazil
cLaboratory of Molecular Pathology, Department of Oral Pathology, Dental School, University of Sao Paulo, Sao Paulo-SP, Brazil
dDepartment of Oral Biology and Center for Craniofacial and Dental Genetics, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, USA
eLaboratory of Pathology, Department of Stomatology, University of São Paulo, Bauru-SP, Brazil
fDepartment of Cell and Molecular Biology, Institute of Biology, Fluminense Federal University, Niterói-RJ, Brazil
gCell and Molecular Biology Center (Nucell), University of São Paulo, São Paulo-SP, Brazil
Corresponding author. Department of Cell and Molecular Biology, Institute of Biology, Fluminense Federal University; Outeiro de São João Baptista, s/n; Campus do Valonguinho; Niteroi – RJ; Brazil; Zip Code: 24.020-150. Tel.: +55 21 2629 2324; fax: +55 21 3701 1617.
1 These authors contributed equally to this study.
ABSTRACT