Morphometric and histopathological evaluation of the effect of grape seed proanthocyanidin on alveolar bone loss in experimental diabetes and periodontitis

Objective Grape seed proanthocyanidine extract (GSPE) is a strong antioxidant derived from the grape seeds (Vitis vinifera, Terral J.F.) and has a polyphenolic structure with a wide range of biological activity. The aim of the present study was to evaluate the effects of GSPE on alveolar bone loss and histopathological changes in rats with diabetes mellitus and ligature‐induced periodontitis. Material and Methods Forty rats were divided into 6 study groups. Control (C, 6 rats) group, periodontitis (P, 6 rats) group, diabetes (D, 6 rats) group, diabetes and periodontitis (D+P, 6 rats) group, diabetes, periodontitis and 100 mg/kg/day GSPE (GSPE‐100, 8 rats), and diabetes, periodontitis and 200 mg/kg/day GSPE (GSPE‐200, 8 rats) group. Diabetes mellitus was induced by intraperitoneal injection of a single dose of streptozotocin (60 mg/kg). Periodontitis was induced via ligation method. Silk ligatures were placed at the mandibular right first molars. GSPE was administered by oral gavage. After 30 days, all rats were killed. Alveolar bone loss was measured morphometrically via a stereomicroscope. For histopathological analyses, Alizarin red staining, and matrix metalloproteinase (MMP)‐8, vascular endothelial growth factor and hypoxia inducible factor (HIF)‐1α immunohistochemistry were performed. Tartrate‐resistant acid phosphatase‐positive osteoclast cells and relative total inflammatory cells were also determined. Results The highest alveolar bone loss was observed in the D+P group (P