2种盖髓剂直接盖髓后大鼠牙髓诱导型一氧化氮合酶的表达变化

An experimental study of expression changes of inducible nitric oxide synthase in rat dental pulp during direct pulp capping with two capping agents

目的观察氢氧化钙(CH)和矿物三氧化物凝聚体(MTA)在大鼠磨牙直接盖髓后诱导型一氧化氮合酶(iNOS)的表达变化。方法 42只雌性Wistar大鼠双侧上下第一磨牙分别用CH和MTA直接盖髓,在观察时点即刻,1、3、7、14、21、28 d处死动物取材,进行iNOS免疫组织化学染色,用图像分析软件测定各组标本中iNOS阳性染色的平均光密度值。用SPSS 11.5统计软件对数据分别进行配对t检验和Dunnett-t检验。结果在正常牙髓组织中iNOS表达呈阴性,CH和MTA直接盖髓后不同时间iNOS表达均呈弱阳性-阳性-弱阳性-阴性的变化,其中盖髓即刻牙髓中iNOS出现低水平表达,3 d时牙髓iNOS出现强阳性表达,7 d后表达开始减弱,21 d后接近正常水平。表达主要位于盖髓剂下方的牙髓组织、成纤维细胞、成牙本质细胞、血管内皮细胞、中性粒细胞等。2种盖髓剂盖髓3 d后iNOS表达强度差异有显著性。结论盖髓剂直接盖髓后,iNOS随时间变化表达呈现先增高后降低的趋势,不同盖髓剂对盖髓3 d时牙髓iNOS的表达强度有影响。

Objective To observe the expression of inducible nitric oxide synthase（iNOS） in rat dental pulp after direct pulp capping with calcium hydroxide（CH） and mineral trioxide aggregate（MTA）.Methods Samples from 42 Wi-star rats were immediately collected at 1,3,7,14,21 and 28 days after direct pulp capping with CH and MTA.Pulp tissues were studided with immunohistochemical stain.Software for image analysis was used to test the optical density of each specimen.The data were analyzed by paired t-test and Dunnett-t test with SPSS 11.5.Results In normal pulp,the stain of iNOS was negative.After direct pulp capping with CH or MTA,iNOS expression demonstrated weakly positive,positive,weakly positive,negative at different time,the expression was low immediately after capping but be-came strong after 3 days.Until 7 days the stain became less positive gradually and at 21 days the stain approached normal.The expression was mainly at the fibroblasts,odontoblasts,vascular endothelial cells,neutrophils,etc near the bottom of the pulp capping agent.The diffence of iNOS expression was significant 3 days after direct pulp capping with this two capping agents.Conclusion After direct pulp capping,iNOS expression increasd at first and then decreased,the diffence of capping agents will have an impact on the expression of iNOS 3 days after direct pulp capping.