Membrane type (MT) 1-matrix metalloproteinase (MMP) and MMP-2 expression in ligature-induced periodontitis in the rat.
BACKGROUND
Matrix metalloproteinases (MMPs) have been shown to be involved in the degradation of the extracellular matrix (ECM). In particular, MMP-2 and MMP-9 (gelatinase A and gelatinase B, respectively) have been identified as the predominant MMPs during periodontitis. Recent studies have indicated that a novel transmembrane MMP, mebrane-type 1 matrix metalloproteinase (MT1-MMP), can activate pro-MMP-2 in tumor metastasis. This study aims to elucidate the presence and localization of MT1-MMP and MMP-2 in periodontitis in a rat model.


METHODS
In 2 groups of 40-day-old male Sprague-Dawley rats, periodontitis was initiated by ligating floss around maxillary second molars. A group of control animals were left untreated. Maxillary dentoalveolar segments were isolated after 7 and 21 days postinduction and were prepared for gross and radiographic analysis of bone loss and for histological analysis. Samples were also prepared for gel zymography to detect the presence of MMP-2, and for Northern blot analysis and in situ hybridization with MT1-MMP probes.


RESULTS
MMP-2 expression increased at 21 days following ligature placement, in conjunction with MT1-MMP expression. MT1-MMP mRNA expression was observed in epithelial cells, fibroblasts, and in multinucleated cells in the periodontium.


CONCLUSIONS
Our data suggest that MT1-MMP may play a role in extracellular matrix degradation during periodontitis, in concert with MMP-2 and other proteinases.
Department of Oral and Maxillofacial Surgery, Louisiana State University School of Dentistry, New Orleans, LA, USA.
Ron
R
Achong
Ichiro
I
Nishimura
Hema
H
Ramachandran
Thomas H
TH
Howell
Joseph P
JP
Fiorellini
Nadeem Y
NY
Karimbux
D000818:Animals; D015152:Blotting, Northern; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D005109:Extracellular Matrix / Q000201:enzymology; D017403:In Situ Hybridization; D008026:Ligation; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000096:biosynthesis*; D023421:Models, Animal; D010518:Periodontitis / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
D004792:Enzyme Precursors; D012333:RNA, Messenger; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2