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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.
RESUMO
This study is to investigate the protective effects of the SB203580 against radiation induced mortality and intestinal injury of mice. A total of 67 male C57BL/6 mice (20.0-22.0 g) were matched according to body weight and randomly assigned to one of three groups: control, total body irradiation exposure (IR, 7.2 Gy) only, and IR (7.2 Gy) + SB203580 (15 mg x kg(-1)). 30 days survival rate was observed in the experiment. In intestinal injury experiment, the expression levels of caspase-3, Ki67, p53 and p-p38 were assayed in the mice intestine crypts. The results showed that the 30 days survival rate was 100% (control), 0 (IR) and 40% (IR+ SB203580), separately. Compared to the IR groups, the positive cells of caspase-3, p53 and p-p38 in crypt cells decreased 33.00%, 21.78% and 34.63%, respectively. The rate of positive cells of Ki67 increased 37.96%. Significant difference was found between all of them (P < 0.01). SB203580 potently protected against radiation-induced lethal and intestinal injury in mice, and it may be a potential radio protector.