Effect Of Mineral Trioxide Aggregate On Proliferation And Differentiation Of Rat Dental Papilla Cells

Objective1.To culture rat dental papilla cells(RDPCs)in vitro, identify and study cell biology character and to provide the cell source for next research.2.To compare the effects of mineral trioxide aggregate (MTA) and calcium hydroxide on the proliferation and differentiation of rat dental papilla cells(RDPCs) and provide the experimental basis for the MTA applied to the apexification.Methods1.To divide tooth germ from the mandible of birth1d SD Department of rats under sterile conditions.RDPCs were cultured by tissue block method and identified, to provide the cell source for next research.2.RDPCs were cultured with material extract fluids containing different mass concentrations of MTA and calcium hydroxide for3d,those cultured with routine culture fluid were served as control group,proliferation-related parameter were measured by MTT assay, then choose the optimal concentration of the two drugs.3.RDPCs were cultured with material extract fluids containing the optimal concentration of MTA and calcium hydroxide respectively,those cultured with routine culture fluid were served as negative control group,the proliferation and differenttiation were examined by MTT assay,activity of alkaline phosphatase(ALP) and level of type Ⅰ collagen of the cells at1,3,5,7d. Results1.RDPCs are identified through HE staining of paraffin sections, cell morphologic observation and immunocytochemistry test. Cultured RDPCs grows good in vitro and the cells present shuttle form or polygons. Strong cell growth is observed at3d and reach peak growth at7d.2.MTA of high concentrations (20mg/ml) and calcium hydroxide of high concentrations(0.018mg/ml) significantly inhibit cells growth.MTA of low concentrations (2mg/ml and less than2mg/ml) and calcium hydroxide of low concentrations(0.012mg/ml and less than0.012mg/ml) can promote cell proliferation (P<0.05)3.Compared with the control group,the proliferation and activity of ALP of RDPCs in MTA group were significantly promoted at3d,5d,7d (P<0.05) and level of type I collagen were significantly promoted at3d,5d.Compared with the calcium hydroxide group, the activity of ALP and level of type I collagen of RDPCs in MTA group were significantly promoted at3d (P<0.05),but the two parameters were no significant increase at5d(P>0.05).Conclusion1. Cultured RDPCs has a good proliferation and differentiation in vitro and can be used as tooth tissue engineering seed cell.2. Compared with calcium hydroxide,MTA can promote the differ-entttiation of RDPCs faster and seal apical tissue earlier,so MTA can replace calcium hydroxide as apical induced materials.