Involvement of Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases in Periodontal Tissue Destruction

采用免疫组织化学方法检测基质金属蛋白酶（MMP）-1、MMP-8和基质蛋白酶组织抑制剂（TIMP）-1在囊肿壁的表达，以了解囊肿生长的机制。对68例根尖囊肿和13例牙源性角化囊肿进行了检测，发现根尖囊肿和牙源性角化囊肿的成纤维细胞、毛细血管内皮细胞、巨噬细胞和衬里上皮细胞均表达MMP-1和TIMP-1，而不表达MMP-8。在根性囊肿中，MMP-1在构成结缔组织壁的总细胞（除淋巴细胞和浆细胞外）中的阳性细胞率显著高于TIMP-1，这种差异在静息型根性囊肿中更为显著MMP-1阳性率为71.2%，TIMP-1阳性率为15.9%，炎症型为64.8%，TIMP-1阳性率为43.2%。根尖囊肿的衬里上皮没有差异，其中大部分细胞出现MMP-1和TIMP-1的免疫反应。在牙源性角化囊肿中，MMP-1的阳性细胞率在衬里上皮中高于TIMP-1，而在结缔组织壁中无明显差异，提示MMP-1和TIMP-1活性平衡的破坏可能是导致囊肿生长的组织破坏的原因。根性囊肿的结缔组织壁和牙源性角化囊肿的衬里上皮分别发生了变化，提示二者的生长机制不同。

The immunohistochemical study on the expression of matrix metalloproeinase (MMP)-1, MMP-8, and tissue inhibitor of matrix proteinase (TIMP)-1 in the cyst wall was designed to understand the mechanism of the cyst growth. Total 68 cases of radicular cyst and 13 cases of odontogenic keratocyst were examined.Fibroblasts, capillary endothelial cells, macrophages, and cells of the lining epithelium in both radicular cysts and odontogenic keratocysts commonly expressed MMP-1 and TIMP-1 but not MMP-8. In radicular cysts, the positive cell rate for MMP-1 to total cells comprising the connective tissue wall, except for lymphocytes and plasma cells, was significantly higher than that for TIMP-1, the difference being more pronounced in the resting type of radicular cyst (71,2% for MMP-1 and 15.9% for TIMP-1) than inflamed type (64.8% for MMP-1 and 43.2% for TIMP-1). There was no difference in the lining epithelium of radicular cyst, in which most of the cells appeared to be immunoreactive for both MMP-1 and TIMP-1. In odontogenic keratocyst, in contrast, higher positive cell rate for MMP-1 compared to that for TIMP-1 was found in the lining epithelium and there was no significant difference in the connective tissue wall.From the present results, it is suggested that the disruption of the balance between MMP-1 and TIMP-1 activities may be responsible for tissue destruction associated with the cyst growth. The change takes place in the connective tissue wall in radicular cyst and in the lining epithelium in odontogenic keratocyst, respectively, suggesting that there is a different growth mechanism between the both.