Figure 4. The alveolar bone from rats ligated for 8 days demonstrated alveolar bone resorption (A). Aminoguanidine treatment suppressed alveolar pathology in the rat alveolar bone (B). A significant increase in the distance between the cemento-enamel junction and the alveolar crest at the mediolingual root of the first molar was observed in ligature-treated rats. (C) Aminoguanidine treatment significantly reduced the increase in the distance between the cemento-enamel junction and the alveolar crest. Densitometry analysis of immunocytochemistry photographs (D; n = 5 photos from each sample collected from all rats in each experimental group) for PAR and nitrotyrosine from gingivomucosal tissue was conducted. The assay was carried out by means of a Macintosh personal computer (CPU G3-266) equipped with Optilab Graftek software. The radiographic Fig. is representative of at least 3 experiments performed on different experimental days. Densitometry data are expressed as % of total tissue area. * P < 0.01 vs. non-ligated. P < 0.01 vs. ligated.