Macrophages subpopulations in chronic periapical lesions according to clinical and morphological aspects

Abstract: The aim of this study was to evaluate macrophage M1 and M2 subpopulations in radicular cysts (RCs) and periapical granulomas (PGs) and relate them to clinical and morphological aspects. M1 macrophages were evaluated by the percentage of CD68 immunostaining associated with the inflammatory cytokine TNF-α, and M2 macrophages, by its specific CD163 antibody. The CD68+/CD163+ ratio was adopted to distinguish between the two macrophage subpopulations. Clinical, radiographic, symptomatology, treatment, and morphological parameters of lesions were collected and a significance level of p = 0.05 was adopted for statistical analysis. The results showed that the CD68+/CD163+ ratio was higher in the RCs (median = 1.22, p = 0.002), and the highest TNF-α immunostaining scores were found in RCs (p = 0.018); in PGs, the CD68+/CD163+ ratio was lower and associated with a greater CD163+ immunostaining (median = 1.02, p <0.001). The TNF-α in cyst epithelium had a score of 3 in 10 cases and predominance of M1 macrophages by CD68+/CD163+ (median = 2.23). In addition, CD68+ cells had higher percentage of immunostaining in smaller RCs (p = 0.034). Our findings suggest that increased CD68 immunostaining associated with TNF-α cytokine in RCs results in a greater differentiation of the M1 phenotype. The higher CD163 immunostaining in PGs results in greater differentiation of the M2 phenotype. Therefore, the inflammatory state promoted by M1 macrophages is related to growth and progression of RCs; on the other hand, the immunomodulatory state of M2 macrophages is related to maintenance of PGs.

摘要：本研究旨在评估根尖周囊肿（radicular cysts, RCs）与根尖周肉芽肿（periapical granulomas, PGs）中的巨噬细胞M1、M2亚群，并探讨其与临床及形态学特征的关联。M1巨噬细胞的评估采用CD68免疫染色（CD68 immunostaining）百分比结合炎性细胞因子肿瘤坏死因子-α（tumor necrosis factor-α, TNF-α）的表达，M2巨噬细胞则通过其特异性抗体CD163（CD163 antibody）进行标记；本研究采用CD68+/CD163+比值区分两类巨噬细胞亚群。研究收集了病变的临床、影像学、症状学、治疗及形态学相关参数，统计学分析以p=0.05作为显著性检验水准。结果显示，RCs的CD68+/CD163+比值更高（中位数=1.22，p=0.002），且其TNF-α免疫染色评分亦更高（p=0.018）；而PGs的CD68+/CD163+比值更低，且伴随更高水平的CD163+免疫染色（中位数=1.02，p<0.001）。在囊肿上皮中，10例病例的TNF-α免疫染色评分为3分，且以CD68+/CD163+标记的M1巨噬细胞占优势（中位数=2.23）。此外，体积较小的RCs中CD68+细胞的免疫染色百分比更高（p=0.034）。本研究结果提示，RCs中与TNF-α细胞因子相关的CD68免疫染色增强，可促进M1表型的分化；而PGs中更高水平的CD163免疫染色则推动M2表型的分化。因此，M1巨噬细胞介导的炎症状态与RCs的生长及进展相关；反之，M2巨噬细胞的免疫调节状态则与PGs的维持有关。