Avaliação da expressão imuno-histoquímica de RUNX-2 durante o reparo ósseo de ratos diabéticos

Abstract

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia. Recent studies have shown changes in bone tissue in diabetic patients. However, few of them evaluate important cell regulatory pathways during bone repair in these patients. This study aimed to evaluate the immunohistochemical expression of the Runx-2 transcription factor in bone repair area in diabetic rats, in order to verify if DM influences osteoblast differentiation. In this study, we used 12 male Wistar rats, Ratthus norvegicus, clinically healthy weighing between 200 and 250g. The animals were separated into 2 experimental groups: Control and Diabetic. DM was induced with the drug streptozotocin (STZ) which promotes the destruction of beta-pancreatic cells. After 30 days, the animals were submitted to bone defect surgery in the left femurs. The bone repair process was evaluated in the experimental period of 7 days post-surgery. The histological sections of the collected femurs were submitted to immunohistochemical analysis that was performed with the indirect polymer-based technique. Scores were assigned for the labeling intensity and the proportion of labeled cells in the bone repair area. Runx-2 expression was observed in osteoprogenitor cells, osteoblasts and osteocytes in both groups. However, after statistical analysis, the results showed lower expression of Runx-2 in the area of bone repair in diabetic animals. This finding allows to conclude that DM alters the differentiation of osteoblasts during bone repair, causing delay of this process.