Expression of runt related transcription factor 2 and vascular endothelial growth factor in the pulp, periodontal ligament and alveolar bone: an immunohistochemical study using a rat ankylotic model.

Abstract

The current study investigated the expression Runx2 and VEGF in the pulp, periodontal ligament and alveolar bone following hypothermal insult. Methods and Materials: Materials from a previous study performed by Tan (2011) were used for this research. The upper right first molars of fifteen eight-week-old male Sprague-Dawley rats were subjected to a single ten minute application of dry ice. The contralateral molar acted as an internal control. The animals were randomly divided into five groups of three and killed 0, 4, 7, 14 and 28 days post hypothermal insult. A further three Sprague-Dawley rats acted as an external control and were humanely killed on day 0 with no hypothermal insult. The maxilla was dissected out, fixed and embedded in paraffin. Coronal sections were cut to include the control and experimental teeth at 5-micron intervals through the furcation region. Sections were then stained with haematoxylin and eosin (H and E) and Runx2 and VEGF immunostains. Sections were scanned via a Nanozoomer Slide Scanner 2.0 series and viewed on a personal computer (MacBook Pro with 13 inch screen) using the Nanozoomer Digital Pathology (NDP) software. Semiquantitative counting was performed at a magnification of x20 via the ImageJ software. Data was analysed using SAS 9.3 (SAS Institute Inc., Cary, NC, USA). The level of significance was set at p<0.05.