Neurogenic component in ligature-induced periodontitis in the rat

Effect of ligation on the vascular permeability in the gingiva and alveolar mucosa encircling the mandibular left 1st molar was studied in rats with and without capsaicin pretreatment. Vascular permeability was assessed by the Evans blue extravasation. Ligation caused a significant augmentation in vascular permeability of the gingivomucosal tissue at day 8 (right: 18.14 +/- 1.68 micrograms g-1; left (ligature): 38.21 +/- 2.43 micrograms g-1, n = 8, p < 0.001) and at day 14 (right: 20.31 +/- 1.71 micrograms g-1: left (ligature): 36.98 +/- 2.73 micrograms g-1, n = 8, p < 0.001). 4 days after ligation, no difference could be observed in vascular permeability in the oral mucosa of the ligated side (left: 23.14 +/- 1.21 micrograms g-1) as compared to the side without ligature (right: 23.5 +/- 1.45 micrograms g-1, n = 8, NS). There was no elevation of vascular permeability of gingivomuscosal tissue around the ligation in rats pretreated with capsaicin either in newborn age (right: 23.92 +/- 1.76 micrograms g-1; left (ligature): 23.51 +/- 2.16 micrograms g-1, n = 8, NS) or in adult age (right: 20.61 +/- 1.62 micrograms g-1; left (ligature): 20.85 +/- 1.07 micrograms g-1, n = 8, NS). Light microscopical studies of oral mucosa revealed, that 8 and 14 days after the ligature placed around the mandibular left 1st molar of the rat, there resulted an accumulation of inflammatory cells in the connective tissue.(ABSTRACT TRUNCATED AT 250 WORDS)