Effects of mechanical stress and interleukin-1beta on collagenase and TIMP-1 expression in human periodontal ligament fibroblasts

Kim, Myung Lip; Bae, Chang

Abstract

The turnover of collagen is controlled by the balance between collagen synthesis and degradation. The production of collagenase (matrix rnetalloproteinase 1) and its inhibitor, tissue inhibitor of matrix metalloproteinase-1(TIMP-1) are one of the substances which rgulate this balance. The periodontal ligament fibrobIast plays an important role in collagen metabolism during orthodontic treatlment and is believed to be an origin of the osteoblast in the alveolar bone. The collagenase secreted by the periodontal ligament fibroblast and the osteoblast initiates the bone resorption by removing the osteoid layer in the alveloar bone. The interleukin 1beta is secreted by the macrophage during orthodontic treatment. The present study was undertaken to assess the effect of mechanical stress and interleukin lbeta on the expression of collagenase and TIMP 1 in the periodontal ligament fibroblasts using reverse transcription polymerase chain reaction and immunohistochemical staining. The periodontal ligament frbroblasts were stretched by placing the Petriperm(R) dish on the top of spheroidal convex watch glass(5% surface increase) and treated with interleukin 1beta (1.0 ng/ml), or treated with both of them. Treatrnent with mechanical stress and/or interleukin 1beta resulted in increased collagenase mRNA expression. The mechanical stress treated group (1.61, 1.62, 1.37 fold increase), the interieukin-1beta treated group, (1.68, 1.60, 3.78 fold increase), the mechanical stress and interleukin-lbeta treated group (1.89, 1.72, 5.48 fold increase) induced increases in collagenase mRNA compared with the control group after 2, 4, 8 hours respectively. But, TIMP-1 mRNA expressions at experimental groups were decreased after 2, 4 hours and increased after 8 hours. The mechanical stress treated group (0.16, 0.49 fold decrease and 3.77 fold incease), the interleukin-lbeta treated group (0.15, 0.44 fold decrease and 4.46 fold increase), the mechanical stress and interleukin-lbeta treated group (0.15, 0.69 fold decrease and 4.81 fold increase) induced changes in TlMP-1, mRNA compated with the control group after 2, 4, 8 hours, respectively. immunohistochemical stain showed that increased collagenase and TIMP-1 staining of the mechanical stress treated group, the interleukin-1beta treated group and the mechanical stress and interleukin-1beta treated group compared with that of the control group after 8hours. These findings suggest that mechanical stress and interleukin 1beta regulate expressions of collagenase and TIMP-1.