人牙冠及根部牙本质内基质金属蛋白酶8，20的测定及分析

背景：基质金属蛋白酶被激活后可降解细胞外基质，其对牙本质胶原的破坏对于牙周病、牙本质龋病、牙髓炎的进展及牙本质黏结的失败有重要影响。目的：检测冠根部牙本质内基质金属蛋白酶的含量及其分布特点。方法：牙本质粉经盐酸胍提取，然后经EDTA循环脱矿，再经盐酸胍提取。采用免疫印迹与免疫酶联吸附反应检测提取物中基质金属蛋白酶8，20的含量，对比二者在牙冠部和牙根部内的分布特点。结果与结论：免疫印迹结果及免疫酶联吸附检测结果均显示，提取物中含有基质金属蛋白酶8，20。未矿化牙本质提取蛋白G1中基质金属蛋白酶8，20含量较低，EDTA反复提取矿化牙本质蛋白E1中含量较高，脱矿后提取蛋白G2中2种基质金属蛋白酶的含量最低。基质金属蛋白酶8，20在牙冠和牙根部表达量基本类似。提示冠根部牙本质中含有基质金属蛋白酶8，20，它们大多存在于矿化牙本质中，其在牙根和牙冠中的含量基本类似。

Characterization and analysis of matrix metalloproteinases 8 and 20 in the human crown and root dentin

BACKGROUND:In recent years, matrix metalloproteinases (MMP)-mediated collagen degradation in dentin has been widely studied. Recent studies have shown that MMPs play an important role in the progress of periodontal disease, dentin caries, pulpitis and failure in dentin adhesive interface.OBJECTIVE:To determine the contents and distribution features of MMP-8 and -20 in the human crown and root dentin.METHODS:Dentin powder was extracted by guanidine hydrochloride, then subjected to ethylene diamine tetraacetic acid demineralization in four cycles, and finally extracted by guanidine hydrochloride again. Extracts were analyzed by Western blot and enzyme linked immunosorbent assay (ELISA) for MMP-8 and -20 detection.RESULTS AND CONCLUSION:MMP-8 and MMP-20 in the extracted materials were confirmed by western blot and ELISA. MMP-8 and -20 were mostly extracted from the mineralized compartment of the dentin (E1). These two MMPs presented overall lower levels in G1 and the lowest levels in G2. Both Western blot analysis and ELISA detected that MMP-8 and -20 equally distributed in the crown and root dentin. MMP-8 and MMP-20 proteins have been found in the extracted materials from the human crown and root dentin. They are mostly presented in mineralized dentin, both in the crown and root dentin.