Objectives: This study aims to examine effect of S.asper leaf-extract and P.gingivalis on regulatory process of primary human osteoblasts.
Methods: Cytotoxicity for various concentrations of sonicated P. gingivalis and S.asper left-extract were tests on primary human osteoblasts (N=3), using MTT assay. Realtime-reverse-transcription PCR was performed to examine expression of RANKL and OPG, osteoblast related inflammatory regulators, in osteoblasts treated with either of tested reagents.
Results: At 2, 12, 24 and 48 hours after treatment, more cell death were found with higher concentrations of the tested agents. At 48 hours after treatment, concentrations of sonicated P.gingivalis that gave 20% (IC20) and 50% (IC50) cytotoxicity were approximately 30.1 and 96.42 μg/ml, respectively. For S.asper leaf-extract, the IC20 and IC50 were 0.14 and 0.32 mg/ml, respectively. At IC20 concentration, sonicated P.gingivalis treated osteoblasts increased RANKL:OPG expression level approximately seven folds ,whereas, the ratio in S.asper treated osteoblasts was slightly decreased when compared to that of the untreated group. Conclusions: In primary human osteoblasts, cytotoxicity of S.asper leaf-extract and sonicated P.ginvivalis seems to be dose dependent. Both tested reagents appear to alter the ratio of expression level of RANKL to OPG, suggesting their roles in modulating inflammatory-response process in primary osteoblasts. This model will be further used for determining effects of S.asper leaf-extract on RANKL and OPG expression in P.gingivalis treated osteoblasts. Support by KKU research fund (grant No 65649)