Imunoexpressão das galectinas-1, -3, e -7 em cistos radiculares, cistos dentígeros e ceratocistos odontogênicos

Abstract

The radicular cyst (RC), dentigerous cyst (DC), and odontogenic keratocyst (OKC) are the most common cystic lesions of the gnathic bones. Although intensively researched, several aspects related to the pathogenesis and biological behaviour of these cysts remain incompletely understood. In this sense, studies have highlighted the involvement of the galectins-1, -3 and - 7 proteins involved in various biological processes, in the development of inflammatoryodontogenic cysts, especially RC. Notwithstanding these important findings, not much is known about the involvement of these proteins in the pathogenesis of DCs and OKCs. Accordingly, this study aimed to assess the immunoexpression patterns of galectins-1, -3, and -7 in RCs, DCs, and OKCs. The sample consisted of 18 RCs, 18 DCs and 18 OKCs from the archives of the Oral Histopathology Laboratory of the Dentistry Department of the State University of Paraíba (UEPB). Clinical data (gender, age and anatomical location) were collected from the biopsy requisition forms. In the morphological study, the RCs were analysed based on the pattern of the epithelial lining (Moreira et al., 2000) and the intensity of the inflammatory infiltrate (Peixoto et al., 2012). In the immunohistochemical study, the percentages of cytoplasmic and nuclear immunopositivity for galectins-1, -3, and -7 were determined in 10 microscopic fields (400×) of the epithelial lining and fibrous capsule of the lesions (Brito et al., 2018). The data obtained were statistically analysed using the Mann- Whitney and Spearman correlation tests (p < 0.05). As for galectin-1 immunoexpression, higher median percentages of cytoplasmic positivity were found in RCs, both in the epithelial lining and the fibrous capsule, with a statistically significant difference relative to OKCs in the epithelial component (p < 0.001). All the groups analysed showed low median percentages of nuclear positivity for galectin-1 in both the fibrous capsule and the epithelial lining (p > 0.05). With regard to galectin-3, both OKCs and DCs exhibited higher median percentages of cytoplasmic and nuclear positivity compared to RCs, in both the epithelial lining and the fibrous capsule (p < 0.001). In this latter location, DCs exhibited significantly higher percentages of nuclear positivity compared to RCs (p < 0.001). Regarding galectin-7 expression in the epithelial lining, DCs showed lower percentages of cytoplasmic positivity compared to OKCs and RCs; however, these differences were not statistically significant (p > 0.05). With regard to the nuclear expression of this protein in the epithelial component, OKCs showed a higher median percentage of positivity compared to DCs (p = 0.001) and RCs (p < 0.001). No significant differences were identified in the immunoexpression of galectins with respect to the morphological characteristics of the RCs (p > 0.05). Significant correlations between the immunoexpression levels of these galectins were also identified (p < 0.05). In conclusion, the results of this study suggest the involvement of galectins-1, -3, and -7 in the pathogenesis of RC, DC, and OKC. Galectin-3 may be particularly important for the development of DC and OKC, whereas galectin-1 may play a more significant role in the formation of RC. On the other hand, the increased nuclear translocation of galectin-7 in the epithelial lining may contribute to the more aggressive biological behaviour of OKC.