目的:研究基质金属蛋白酶3(MMP-3)对牙髓损伤后修复性牙本质形成的作用. 方法:取48只Wistar大鼠,分为3组(n=16);在各组大鼠的左侧上颌第一磨牙牙合面备洞至露髓后,分别用PBS、氢氧化钙、MMP-3(均以胶原蛋白海绵做载体)盖髓. 于术后3、7、14、28 d各时间点,每组各随机处死4只动物,制备实验牙组织切片;HE和免疫组化染色,观察各组修复性牙本质形成及成牙本质细胞中DMP-1 的表达情况.结果:MMP-3组在盖髓后DMP-1的表达情况:3 d时,呈弱阳性表达;7 d时,呈阳性表达,露髓点下方可见散在的骨样牙本质;14 d时,呈强阳性表达,露髓点下方可见连续完整的钙化桥;28 d时,表达明显减弱,露髓点下方可见大量修复性牙本质. 各时间点各组成牙本质细胞中DMP-1 阳性区的灰度值均以MMP-3 组最高, PBS组最低;MMP-3组与PBS组相比,在术后3、7、14 d时均有显著性差异(P<0. 05);MMP-3组与氢氧化钙组相比,在术后3、7 d时有显著性差异(P<0. 05). 结论:MMP-3对牙髓损伤后修复性牙本质的形成具有促进作用.%AIM: To study the role of MMP-3 on the reparative dentin formation after pulp injury. METHODS:48 Wistar rats were divided into 3 groups(n=16). A cavity on the occlusal surface of maxillary first mo-lars on left side was prepared in each rat, PBS, calcium hydroxide, and MMP-3 was applied on the exposed pulp in the rats of the 3 groups respectively. On day 3, 7, 14 and 28 after operation, the rats were sacrificed. The tooth were stained with HE and immunohistochemistry. DMP-1 expression was observed. RESULTS:In MMP-3 group, DMP-1 was weakly expressed on d 3, positively expressed on d 7 and strongly expressed on d 14, but its expression decreased on d 28 in odontoblasts. A large number of scattered osteoid dentin was observed under the exposed pulp on d 7. Con-tinuous calcified bridge was observed under the exposed pulp on d 14 . A thick layer of reparative dentin was observed under the exposed pulp, MMP-3 group showed stronger DMP-1exoression(P<0. 05) and more reparative dentin than PBS group at each time point, and than calcium hydroxide group on d 3 and d 5. CONCLUSION:MMP-3 may pro-mote the repair of dental pulp after injury.
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