2010 Volume 53 Issue 6 Pages 601-610
Diabetes mellitus is considered to be an important risk factor for periodontal disease, which is now regarded as the sixth complication of diabetes mellitus following retinopathy, diabetic nephropathy, neuropathy, microvascular disorder and macroangiopathy. All of these complications are attributed to angiopathy. In this study, for purpose of determining the effect of diabetes mellitus on recovery of microcirculation in the early wound healing process, localization of VEGF during wound healing was examined immunohistochemically for periodontal defects created artificially in the molar region of Goto-Kakizaki (GK) rats, which are model rats with type II diabetes mellitus, and the ultrastructural morphology of their microvessels newly developed was observed. Eight-week-old rats were separated between SD and GK and referred to as the control group and the experimental group, respectively. Palatal dehiscence defects were surgically created on the bilateral maxillary first molars in SD and GK rats. Six rats from each group were euthanized on each of days 3, 5 and 7 after surgery, and the periodontium including maxillary first molar was removed and decalcified after performing perfusion fixation. Following decalcification, paraffin sections were created for four rats of each group, immunostaining was performed on VEGF, and observations were made with a light microscope. For the remaining two rats, ultrathin sections were created by embedding them in Epon 812 with resin and were observed with a transmission electron microscope. As a result, localization of VEGF occurred to the rats of both groups in the periodontal defect region on days 3 and 5 after surgery. Additionally, VEGF was strongly localized, especially around the capillaries of the rats from the experimental group and active formation of new capillaries was also confirmed. Although VEGF was rarely localized in the rats of the control group on day 7 after surgery, localization occurred to the rats of the experimental group around the capillaries in the periodontal defect region, and the formation of new vessels was confirmed. It is suggested that the recovery of microcirculation for healing of defects in periodontal tissue is adversely affected since the expression of VEGF was promoted in the experimental group compared with the control group, and the continuous formation of new vessels and enhancement of vascular permeability in the surgical site were confirmed throughout the experimental period, and therefore stronger expression of VEGF occurred in the experimental group by creating hypoxia in the periodontal defect region.
