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

我们用免疫组织化学方法检测了实验性大鼠牙髓炎和根尖周病变中巨噬细胞、iNOS阳性细胞、Ia抗原阳性细胞和PGP9.5免疫反应神经纤维的分布。结果表明：1）牙髓中巨噬细胞在牙髓暴露后0.5天至1周内数量增加，2周后消失;在根尖周牙周组织中，巨噬细胞在治疗后4周增加，此后减少。PGP9.5免疫反应神经纤维的变化与巨噬细胞数量的变化密切相关。2）牙髓中iNOS阳性细胞和Ia抗原阳性细胞数量在治疗后1周内明显高于对照组。但各细胞的分布不同，iNOS阳性细胞多位于脓肿附近，Ia抗原阳性细胞则位于较远的脓肿周围。在根尖周组织中，Ia抗原阳性细胞在治疗后1周增加，此后几乎消失。与此相反，在根尖孔附近，iNOS阳性细胞在2周和8周之间观察到，考虑到这些结果，iNOS阳性细胞可能发挥更重要的作用比Ia抗原阳性细胞在前线防御，似乎没有什么关系根尖周组织破坏。

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.