Immunoexpression of bone resorption biomarkers in apical periodontitis in diabetics and normoglycaemics

To compare the immunoexpression of RANK, MMP-9 and PTHrP in apical periodontitis lesions of diabetic and normoglycaemic individuals.

Primary chronic apical periodontitis lesions associated with teeth indicated for extraction in 13 type 2 diabetic individuals and 13 normoglycaemic individuals who were screened for the glycaemic index and glycated haemoglobin (HbA1c) were analysed. Individuals with other systemic diseases and users of anti-inflammatories and/or antibiotics in the previous 3 months were excluded. Silanized slides with paraffin sections were used for immunohistochemical reactions and stained with haematoxylin and eosin for histopathological classification. The images were analysed with an optical microscope, and the slides were subdivided into five large fields assigning scores (0-2), according to the number of positive markings for each antibody. Fisher's exact test evaluated the parameters: gender, type of lesion, location and position in the arch. Nonparametric Mann-Whitney test was used for age, HbA1c values and comparison of marker expression. The chi-squared test was used to associate the expression of the markers. And the Spearman's coefficient correlated the markers with the size of the periapical lesion.

The samples consisted of 69% periapical granulomas and 31% periapical cysts in each group. RANK expression was considered weak/moderate and strong in, respectively, 62% and 38% of the cases in both groups. MMP-9 expression was weak/moderate and strong in, respectively, 38% and 62% of the cases from the diabetic group, in comparison with 38% and 38% in the normoglycaemics (24% cases from this group were negative). In contrast, PTHrP expression was negative, weak/moderate and strong in, respectively, 46%, 46% and 8% of the cases from the diabetic group, in comparison with 38% negative and 62% weak/moderate in normoglycaemics. Quantitative analysis revealed that there were no significant differences in the immunoexpression of RANK (P = 0.26), MMP-9 (P = 0.17) and PTHrP (P = 0.43) between the groups. There was no significant correlation between the expression of bone resorption markers and the macroscopic size of the periapical lesions (P > 0.05).

The bone resorption mediators analysed had similar immunoexpression in the periapical lesions of diabetic and normoglycaemic individuals.