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目的观察大鼠磨牙应用矿物三氧化物凝聚体(MTA)直接盖髓术后牙髓组织中转化生长因子-β1(TGF-β1)的表达变化及其在牙髓损伤修复中的作用。方法本研究于2012年10月至2013年3月在中国医科大学口腔医学院中心实验室进行。28只雌性Wistar大鼠第一磨牙机械穿髓后用MTA直接盖髓,并以对侧第一磨牙为对照,分别于术后1、3、5、7、14、21、28d处死动物并取材(每次处死4只),进行免疫组化染色,观察TGF-β1在牙髓组织的动态表达和定位情况,用图像分析软件测定各组标本中TGF-β1阳性染色的光密度值。结果在正常牙髓组织中TGF-β1基本无表达,MTA直接盖髓后TGF-β1表达强度呈先升高后降低的基本变化,其中盖髓后5d的TGF-β1表达最强,21d时接近正常水平。表达主要位于盖髓剂下方中性粒细胞、成牙本质细胞、成纤维细胞和血管内皮细胞。结论 MTA直接盖髓后,TGF-β1可能参与牙髓的损伤修复过程。
Objective To investigate the expression of transforming growth factor-β1 (TGF-β1) and its role in the restoration of dental pulp injury after toothpuller application of mineral trioxide aggregate (MTA). Methods The study was conducted from October 2012 to March 2013 at the Central Laboratory of Stomatology, China Medical University. Twenty-eight female Wistar rats with first molars were mechanically implanted and then directly capped with MTA. The contralateral first molar was used as a control and the animals were sacrificed at 1, 3, 5, 7, 14, 21 and 28 days after operation (4 in each sacrifice). Immunohistochemical staining was performed to observe the dynamic expression and localization of TGF-β1 in pulp tissue. The optical density of TGF-β1-positive staining in each group was determined by image analysis software. Results The expression of TGF-β1 was almost unchanged in normal pulp tissue. The expression level of TGF-β1 increased first and then decreased in MTA treated directly. The expression of TGF-β1 was the highest at 5 days and reached the maximum at 21 d normal level. The expression is mainly located below the pulp capsule neutrophils, odontoblasts, fibroblasts and vascular endothelial cells. Conclusion After the direct capping of MTA, TGF-β1 may be involved in the injury and repair process of dental pulp.