Methods: Experimental periodontitis was induced in adult male Sprague-Dawley rats by placing a nylon thread ligature around the bilateral lower 1st molars. These animals were divided into four groups randomly (9 animals each) as follows: ligation alone (L), L+50mg/kg baiclin, L+100mg/kg baicalin, L+200mg/kg baicalin. The control group received no periodontitis induction. All animals were treated daily with 0.5% carboxymethyl cellulose (CMC) alone or containing above mentioned different dosages of baicalin orally one day before periodontitis induction. At the end of the 1-week protocol, the rats were sacrificed. Alveolar bone loss (ABL) was measured in one side jaw as the distance between the cemento-enamel junction and the alveolar bone. The area fraction (AA %) occupied by collagen fibers stained by sirius red F3Ba in gingival connective tissue were analyzed in another quadrant. In vitro, the effect of baicalin on MMP-1 protein and mRNA expression induced by IL-1b in human PDLC were detected by enzyme-linked immunosorbent assay (ELISA) and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR).
Results: Intergroup comparisons demonstrated that all dosages of baicalin reduced ABL as compared to group L. Moreover, there was significant difference between group L+ 200mg/kg baicalin and group L(P<0.05). The group treated with 200mg/kg baicalin also had the higher AA% of collagen fibers in comparison to group L (P<0.05). Bacalin (100ng/ml) could down-regulate of MMP-1 protein and mRNA expression in PDLC induced by IL-1bin vitro (P<0.05).
Conclusions: Baicalin may reduce bone loss and collagen degradation associated with experimental periodontitis. These effects might be related to down-regulation of MMP-1 protein level and mRNA expression.