Effects Of Different Dental Alloys On Cytotoxic And Apoptosis Related Genes Expression Of L929 Cells

Objectivevarious forms of corrosion would develop when dental alloys functions in mouth, cytotoxicity is one of the most important problems in medical metal materials.with the rapid development of moleculor biology,the mothods of study the biocompatability of biomaterials have been more and more diversification and their evaluation have been raised from the cell lever to molecular lever, the effects of the leaching liquids of 5 different kinds of dental alloys to L929 cell on cell lever and molecular lever was compared by MTT and RT-PCR method.this study provids experiment evidences for evaluting biocompatibility of materious on molecular lever.Material and Methods1. Cells cultrueL929 cells are cultivated and passaged with RPMI 1640 cell medium containing 10% fetal calf serum in the incubator of 37℃and 5% CO₂.2.The cell growth curve of L929 cell in the laboratoryThe L929 cell in exponential phase of growth was made to 10 different concentration 1～10×10⁴/ml). after 72h incubation, MTT liquor was added and after 4 h DMSO was added. OD value was estimated at 490 nm wave and the density mean was put in computer for plotting.3.MTT assayThe density of cell suspension was determined according to the result of cell growth curve, L929 cell was cultured by the leaching liquids of 5 different kinds of dental alloys and negative control for 48 hours, and then cell proliferation rate was calculate by OD value.4.RT-PCRL929 cell was cultured with 5 dental alloys' leaching liquor and their negative controls for 48 hours,and then detect the mRNAexpression of cells' caspase-3,caspase-8 and caspase-9.Results1.The result of cell growth curveThe difference was not obviously when less than 4000 cells were seeded in each well.However,The OD value was depressed when more than 7000 cells were seeded in each well. The best state for the cells was 5000-7000 per well.2.The cytotoxicities of the 5 dental alloys were evaluated by means of MTTThe results indicated that the cytotoxicity of Cu alloy group was in Grade 4 and those of the other groups were all in Grade 0 after 48 hours culture.3.The effect of five dental alloys on the mRNA expression of caspase-3,caspase-8 and caspase-9The mRNA levels of caspase-8 had no change in all groups. The mRNA levels of caspase-3 and caspase-9 were as follows from low to high: Cu alloy,the negative control and Au alloy,Co-Cr alloy,Ag-Pd alloy,and Ni-Cr alloy.Conclusions(1)It is more sensitive to study the affect of five dental alloys to L929 cells on molecular lever than cell lever.(2)Metal ions of 5 dental alloys may induce cell apoptosis by different degree through mitochondrion pathway.(3)The mRNA levels of caspase-3 and caspase-9 were as follows from low to high: Cu alloy,the negative control and Au alloy,Co-Cr alloy,Ag-Pd alloy,and Ni-Cr alloy after 48 hours' culture.