Temporal and dynamic changes in gingival blood flow during progression of ligature-induced periodontitis.

OBJECTIVES

To evaluate temporal changes in gingival blood flow (GBF) during progression of periodontitis in rats using a laser Doppler flowmeter (LDF) approach and to characterize morphological and biochemical features in the periodontium associated with GBF.

MATERIALS AND METHODS

Forty-two Wistar rats were divided into a ligature-induced periodontitis group and a control group. To induce periodontitis, ligatures were tied around maxillary first molars bilaterally. GBF was measured in palatal gingiva at pretreatment and following ligature placement after 30 min, 1, 3, 7, 14, 21, and 28 days using LDF with a non-contact probe. Bone loss and gene expression in gingival tissues were assessed using micro-computed tomography (μCT) and quantitative polymerase chain reaction (PCR), respectively. Immunostaining for vascular endothelial growth factor (VEGF) in the maxilla was also histologically evaluated.

RESULTS

GBF in the ligature group increased significantly compared with the control group 30 min after ligation. However, on days 3 and 7, GBF decreased in the ligature group. Also, after day 10, there was no difference in GBF between groups. The levels of alveolar bone loss, gene expression (interleukin-6, cluster of differentiation-31, VEGF-A, and lymphatic vessel endothelial hyaluronan receptor-1), and immunostained VEGF-positive vessels correlated well with changes in GBF. CONCLUSION PROGRESSION OF PERIODONTITIS: In rats was associated with a triphasic pattern of GBF, consisting of a short initial increase, followed by a rapid decrease, and then a gradual plateau phase.