RESUMEN
Aim To establish the 3D hepatocyte model by selecting the humanized hepatocyte HepG2 cells and 3D cell culture methods, and to establish the 3D hepatocyte cytokinesis-block micronucleus cytome(CBMN-cyt)assay and 3D hepatocyte comet assay by using chemicals of different mode of action.Methods In this study, a scaffold-free culture method was used to successfully establish a 3D HepG2 hepatocyte spheroid model.The appearance of the sphere, the survival rate of cells inside the sphere, the gene expression of phase I and II metabolic enzymes, and the expression of liver-specific biomarkers were selected as the observation indicators to obtain the best culture conditions for the 3D hepatocyte model.The 3D hepatocyte model was combined with in vitro micronucleomics test and in vitro comet test to explore its applicability for genotoxicity test.Results The best culture conditions for the 3D hepatocyte model was 5×103 cells/20 μL /drop inoculation, cultivating for seven days.A 3D hepatocyte CBMN-cyt assay was established using mitomycin C(MMC), a micronucleus positive compound, and the results showed that it could successfully detect the genotoxicity and cytotoxicity of MMC.Compared with the CBMN-cyt results of 2D hepatocyte model, 3D hepatocyte model had higher sensitivity in detecting MN and Nbud.The 3D hepatocyte comet assay methods were established using the known in vivo and in vitro comet assay positive compound methyl methanesulfonate(MMS), and the results showed that MMS could significantly increase the tail DNA% of 3D hepatocytes with low cytotoxicity.The sensitivity of 3D hepatocyte model to MMS genotoxicity detection was higher than that of 2D cells.Conclusions The 3D hepatocyte model established in this study is easy to use and low in cost, and shows good sensitivity and specificity in the in vitro micronucleus test and comet test, suggesting that the 3D hepatocyte genotoxicity test method is used in early drug genotoxicity screening.It has good application prospects in additional experimental research.