Estudo imunoistoquímico das subpopulações de macrófagos em cistos radiculares e granulomas periapicais de acordo com aspectos clínicos e morfológicos

Abstract

Introduction: Radicular cysts (RCs) and periapical granulomas (PGs) develop in response to inflammatory mediators from pulp necrosis. Macrophages play an important role in the etiopathogenesis of these lesions and are involved in the protective response of the host as well as in the perpetuation of inflammatory reactions. The infiltration of macrophages subpopulations M1 and M2 into sites of chronic inflammation allows the phagocytosis of foreign agents, the release of chemical mediators and may also act as antigen-presenting cells. Aim: To identify the subpopulations of macrophages M1/M2 in RCs and PGs, additionally relates them to clinical and morphological aspects. Material and Methods: A clinic, histopathologic and immunohistochemical analysis were performed on 30 RCs and 30 PGs. The M1 macrophages subpopulation was evaluated by the percentages of CD68 immunostaining associated with the TNF-α inflammatory cytokine and the M2 macrophages subpopulation by its specific CD163 antibody. Clinical, radiographic, symptomatology, treatment and morphological parameters of the lesions were collected and a statistical significance level of 95% was adopted for statistical analysis. Results: The ratio of CD68+/CD163+ cells was higher in the RCs (median=1.22, p=0.002), and the highest TNF-α immunostaining scores were found in the RCs (p=0.018); in the PGs, the CD68+/CD163+ ratio was lower and associated with a greater CD163+ immunostaing (median=1.02, p<0.001). In addition, CD68+ cells had higher percentages of immunostaining in RCs with smaller sizes (p=0.034). Conclusion: The increased CD68 immunostaining associated with TNF-α cytokine in RCs suggests the greatest differentiation for a M1 phenotype. The greater CD163 immunostaining in PGs provide greater differentiation for the M2 phenotype. Therefore, the inflammatory state promoted by the M1 macrophages is related to appearance and maintenance of RCs, on the other hand, the immunomodulatory state of the M2 macrophages is related to the development of PGs.