Avaliação imunoistoquímica das galectinas -1, -3 e -7 em granulomas periapicais, cistos radiculares e cistos radiculares residuais

Abstract

Studies demonstrate that galectins are involved in the development of immunoinflammatory response, by regulation of homeostasis and immune cell functions. However, the function of these lectins in the development of periapical lesions are scarce in the literature. The objective of this study was to evaluate, through immunohistochemistry, the expression of galectinas -1, -3 and -7 in periapical granulomas (PGs), radicular cysts (RCs), and residual radicular cysts (RRCs), related this with morphological parameters (intensity of the inflammatory infiltrate and the thickness of the cystic epithelial lining). The sample consisted of 20 periapical granulomas (PGs), 20 radicular cysts (RCs), and 20 residual radicular cysts (RRCs) were submited to immunohistochemistry. The inflammatory and epithelial cells were quantified from nuclear and/or cytoplasmic/membrane expression and their percentage submited for statistical evaluation. The results for the morphological analysis revealed that 100% of GPs and 80% of CRs showed an intense inflammatory infiltrate (grade III), and to CRRs, 60% had a mild inflammatory infiltrate (grade I). The analysis of epithelial lining in cystic lesions showed that atrophic ephitelium was observed in 65% of CRRs and 50% of the RCs, the hyperplastic ephitelium was demonstrated, respectively, in 50% and 35% of the RCs of CRRs. Immunohistochemical evaluation of each galectin in connective tissue demonstrated that GPs exhibited higher expression of galectin -1 in relation to RCs and CRRs in both components (nucleus and cytoplasmic/membrane) of inflammatory cells (p <0.05). Additionally, lesions that exhibit inflammation grade II had an increased expression of galectin-1 in both cell components (p <0.05). Galectin-3 showed no differences statistically significant in inflammatory cells of connective tissue (p> 0,05). In Galectin-7, GPs showed a higher immunoreactivity of this protein in cytoplasmic/membrane component, compared to CRs and CRRs (p <0.05) and independently of the type of lesion, those with inflammatory infiltrate grade III had greater immunoreactivity of galectin-7 (p <0.05). In the epithelial lining, galectins -1 and -3 showed no statistically significant differences of immunoreactivity (p> 0.05). However, the immunohistochemical expression of galectin-7 revealed that epithelial lining of CRRs showed a higher percentage of nuclear expression than CRs epithelial lining (p = 0.014). Lesions with hyperplastic epithelium showed a greater cytoplasmic/membrane positivity than lesions with atrophic epithelium (p=0.020). Positive correlations were observed to each galectin on epitelial and connective tissues. In addition, positive correlations were observed between galectins -1 and -7 into connective tissue (p <0.001), independent the type of lesion. In conclusion, the results of this study show the involvement of these proteins in the modulation of immunoinflammatory response among periapical lesions.