RESUMO
PURPOSE: To detect the degradation of Ca(OH)2 on lipopolysaccharide (LPS) extracted from Porphyromonas endodontalis (P.e) in vitro and estimate the influence of P.e LPS pretreated with Ca(OH)2 on the proliferation of MC3T3-E1 cells. METHODS: The effect of Ca(OH)2 on MC3T3-E1 cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay. Then P.e LPS was treated with Ca(OH)2 for 30 mins or 60 mins at 37 degrees centigrade in vitro and the activity of P.e LPS was evaluated by Chromogenic End-point Tachypleus Amebocyte Lysate (CE TAL) test. Finally, MC3T3-E1 cells were exposed to P.e LPS pretreated with 15% Ca(OH)2 for 1, 3 and 5 d, and the cell proliferation was measured using the MTT assay comparing with the P.e LPS control group. SPSS 13.0 software package was used for statistical analysis. RESULTS: Compared with the negative control, exposing cells to 5%, 10% and 15% Ca(OH)2 had greatly promoted MC3T3-E1 cell proliferation. P.e LPS treated with 10% and 15% Ca(OH)2 both presented the best results by CE TAL and significant difference compared with P.e LPS control group. When 10 µg/mL P.e LPS was pretreated with 15% Ca(OH)2, no inhibition of MC3T3-E1 cell proliferation was noted. CONCLUSIONS: Ca(OH)2 detoxifies P.e LPS in vitro, mitigates the impact of P.e LPS on MC3T3-E1 cell proliferation. Supported by Science and Technology Projects of Liaoning Province (2011225020).