Mechanical Tensional Force Regulates Collagen Maturation and Degradation in Human Periodontal Ligament Cells- Expression of LOX and MMPs
Date Issued
2009
Date
2009
Author(s)
Huang, Ming-Yen
Abstract
The periodontal ligament (PDL) has a relatively high turnover rate and can therefore quickly adapt to mechanical forces, application during orthodontic tooth movement. PDL and its surrounding tissue are composed of fibroblasts, osteoblasts, cementoblasts, epithelial cells, endothelial cells, and osteoclasts, as well as the extracellular matrix (ECM), of which the major components are the type I and III collagens. Collagens connect the alveolar bone and cementum on the surface of the tooth root, while maintaining the PDL space and providing a three-dimensional scaffold for those cells around the PDL. esides the remodeling of alveolar bone around the moving teeth, the major extracellular matrix (ECM) components of PDLs, collagens, are degenerated, degraded, and restructured. Lysyl oxidase(LOX) catalyses the cross-linking of fibrillar molecule of type I collagen into mature insoluble extracellular matrix. On the other hand，matrix metalloproteinases (MMPs) and their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs), acting in a co-ordinated fashion to degrade collagen and to regulate the remodeling of periodontal tissues. he purpose of our study was to investigate expression of LOX，MMP-2，and MMP-9，which involve in the process of collagen synthesis，stabilization and degradation in the human periodontal fibroblasts subjected to mechanical stretch. Flexercell® strain unit was used to transmit 0.5 Hz, 3% and 10% equibiaxial tensile force to human periodontal fibroblasts cultured on Type I collagen coated silicone membrane. The biological response was assessed at protein levels. ur results revealed that the expression of LOX enzyme was up-regulated in the periodontal fibroblasts subjected to 3% cyclic mechanical stretch for 24 hours or 48 hours. Meanwhile the increased level of LOX was also noted in the culture medium. These responses diminished after the cells rested for another 48 hours. Compared to 3% stretch, 10% stretch did not produce more significant effect. After being subjected to 3% and 10% mechanical stretch, the levels of MMP-2，the enzyme involved in collagen catabolism，was significantly increased both in the cell layer and in culture medium. The effect of both stretch group were similar in cell layer but the effect of 10% stretch group was more obvious in culture medium. Contrary to MMP-2，the expression of MMP-9 was not noted for cell layer. Possibly, its level was too low to be detected in our system. However，MMP-9 was detected in the culture medium. The level of MMP-9 was induced by 3% and 10% cyclic mechanical stretch，and the effect was more obvious in 10% stretch group. Our data demonstrated that mechanical loading conditions that generated tensional force resulted in an increase in extracellular matrix synthetic events and also in matrix degradative events. The higher levels of LOX，MMP-2，and MMP-9 seen in the periodontal cellular responses to mechanical tensional force may be critically involved in the delicate process regulating the mechanically-induced ECM remodeling of periodontal ligament.
Subjects
periodontal ligament
cyclic tensional force
collagen
lysyl oxidase
MMP-2
MMP-9
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-R95422017-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):1b5c49c92be5a1fd093403a5be8a8fa4