Inhibitory effects of Persicariae Rhizoma aqueous extracts on experimental periodontitis and alveolar bone loss in Sprague-Dawley rats

Persicariae Rhizoma (PR) is the dried stem parts of Persicaria tinctoria H. Gross (Polygonaceae), and has been traditionally used as anti-inflammatory and detoxifying agent. In the present study, the effects of PR aqueous extracts on ligation-induced experimental periodontitis (EPD) and associated alveolar bone loss in rats were examined. Following the induction of EPD in rats, PR extracts were orally administered once a day for 10 days, and the changes and gains in body weight, alveolar bone loss and total aerobic bacterial counts of buccal gingiva were observed with histopathological analysis. In addition, anti-inflammatory effects were evaluated by monitoring myeloperoxidase (MPO) activities, and interleukin (IL)-1β and tumor necrosis factor (TNF)-α contents, and anti-oxidant effects were investigated by measuring inducible nitric oxide synthase (iNOS) activities and malondialdehyde (MDA) levels. Bacterial proliferation, periodontitis and associated alveolar bone loss induced by ligature placement were significantly and dose-dependently inhibited by the treatment with PR extracts. The inhibitory effects of 200 mg/kg PR were similar to those of 5 mg/kg indomethacin on ligation-induced periodontitis and associated alveolar bone losses in this study. The results suggest that PR effectively inhibits ligature placement-induced periodontitis and alveolar bone loss in rats via antibacterial, antioxidative and anti-inflammatory activities.