Immunohistochemical examination on the role of nitric oxide in the experimentally induced periapical lesions.

采用免疫组化方法观察实验性大鼠牙髓炎和根尖周围病变中巨噬细胞、inos阳性细胞、Ia抗原阳性细胞和pgp9.5免疫反应性神经纤维的分布。所得结果如下：1)牙髓内巨噬细胞在暴露后0.5天至1周内数量增加，治疗后2周消失。在根尖周组织中，巨噬细胞在治疗后4周增加，随后减少。pgp9.5免疫反应性神经纤维的变化与巨噬细胞数量的变化密切相关。2)治疗组牙髓中inos阳性细胞和Ia抗原阳性细胞的数量明显多于对照组，直至治疗后1周。但各细胞分布不同，在脓肿附近有inos阳性细胞，而离脓肿较远的地方有Ia抗原阳性细胞。在根尖周组织中，Ia抗原阳性细胞在治疗1周后增加，此后几乎消失。相反，在2周至8周期间，在根尖孔附近观察到inos阳性细胞。考虑到这些结果，我们认为inos阳性细胞可能比Ia抗原阳性细胞在前线防御中发挥更重要的作用，而与根尖周围组织破坏的关系似乎不大。

We examined immunohistochemically the distribution of macrophages, iNOS-positive cells, Ia antigen-positive cells and PGP9.5-imunoreactive nerve fibers in eperimentally induced rat pulpitis and periapical lesions. The results obtained were as follows.1) In the pulp, macrophages increased in number from 0.5 days to 1 week after pulp exposure and disappeared 2 weeks after treatment. In the periapical periodontial tissues, macrophages increased until 4 weeks after treatment and decreased thereafter. The changes of PGP9.5-imunoreactive nerve fibers were closely related with the alteration in number of macrophages.2) In the pulp, the number of iNOS-positive cells and Ia antigen-positive cells increased in the treated group much more than that in the control group until 1 week after treatment. However, the distribution of each cells was different , iNOS-positive cells were found near the abscess but Ia antigen-positive cells were a little remote from the abscess. In the periapical tissues, Ia antigen-positive cells increased 1 week after treatment and disappeared almostly thereafter. On the contrary, iNOS-positive cells were observed near the apical foramen between 2 weeks and 8 weeks.Taken these findings into consideration, it was suggested that iNOS-positive cells might play a more important role than Ia antigen-positive cells in the front-line defense and seemed to have little relationship with periapical tissue destruction.