Department of Operative Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599, USA.
Int J Oral Sci. 2011 Oct;3(4):192-9. doi: 10.4248/IJOS11070.
The presence of matrix metalloproteinase-2 (MMP-2) in dentin has been reported, but its distribution and activity level in mature human coronal dentin are not well understood. The purpose of this study was to determine the MMP-2 distribution and relative activity in demineralized dentin. Crowns of twenty eight human molars were sectioned into inner (ID), middle (MD), and outer dentin (OD) regions and demineralized. MMP-2 was extracted with 0.33 mol x L(-1) EDTA/2 mol xL(-1) guanidine-HCl, pH 7.4, and MMP-2 concentration was estimated with enzyme-linked immunoabsorbant assay (ELISA). Further characterization was accomplished by Western blotting analysis and gelatin zymography. The mean concentrations of MMP-2 per mg dentin protein in the dentin regions were significantly different (P = 0.043): 0.9 ng (ID), 0.4 ng (MD), and 2.2 ng (OD), respectively. The pattern of MMP-2 concentration was OD > ID > MD. Western blotting analysis detected -.66 and -72 kDa immunopositive proteins corresponding to pro- and mature MMP-2, respectively, in the ID and MD, and a -66 kDa protein in the OD. Gelatinolytic activity consistent with MMP-2 was detected in all regions. Interestingly, the pattern of levels of Western blot immunodetection and gelatinolytic activity was MD > ID > OD. The concentration of MMP-2 in human coronal dentin was highest in the region of dentin that contains the dentinoenamel junction and least in the middle region of dentin. However, levels of Western blot immunodetection and gelatinolytic activity did not correlate with the estimated regional concentrations of MMP-2, potentially indicating region specific protein interactions.
已有研究报道基质金属蛋白酶-2（MMP-2）存在于牙本质中，但人们对成熟人冠部牙本质中 MMP-2 的分布和活性水平了解甚少。本研究旨在确定脱矿牙本质中 MMP-2 的分布和相对活性。28 个人类磨牙的牙冠被切成内（ID）、中（MD）和外牙本质（OD）区并进行脱矿处理。用 0.33mol/L EDTA/2mol/L 盐酸胍（pH7.4）提取 MMP-2，并用酶联免疫吸附试验（ELISA）测定 MMP-2 浓度。通过 Western 印迹分析和明胶酶谱进一步进行特征分析。牙本质各区每毫克牙本质蛋白中 MMP-2 的平均浓度差异具有统计学意义（P=0.043）：ID 区 0.9ng、MD 区 0.4ng 和 OD 区 2.2ng。MMP-2 浓度的模式为 OD>ID>MD。Western 印迹分析在 ID 和 MD 区检测到分别对应于 pro-MMP-2 和成熟 MMP-2 的-66 和-72kDa 免疫阳性蛋白，在 OD 区检测到-66kDa 蛋白。所有区域均检测到与 MMP-2 一致的明胶酶活性。有趣的是，Western 印迹免疫检测和明胶酶活性的水平模式为 MD>ID>OD。人冠部牙本质中 MMP-2 的浓度在含有牙本质牙釉质交界处的区域最高，在牙本质的中间区域最低。然而，Western 印迹免疫检测和明胶酶活性水平与 MMP-2 的估计区域浓度没有相关性，可能表明存在区域特异性蛋白相互作用。
