| Objective: (l) To establish an efficient and simple method for purification and culture of bone mesenchymal stem cells (BMSCs). (2) To find an appropriate concentration of fluorescent magnetic nanoparticles (FMNPs) to label bone marrow mesenchymal stem cells. (3) To test the results of FMNPs labeled BMSCs in vitro. (4) To investigate the capability of rat BMSCs home to gastric cancer.Methods: (1) BMSCs were harvested and purified from rats by adherent culture and then BMSC expression of CD29, CD90 and CD45 were detected by flow cytometry. To evaluate their ability to differentiate into multi-lineage cells, BMSCs were cultured in different induced media; (2) BMSCs were co-cultured with FMNPs and then tested their survival rate under different concentrations and periods to screen out the appropriate concentration of FMNPs. Prussian blue staining, laser scanning confocal microscope, magnetic resonance imaging technology were used to observe labeled BMSCs in vitro after co-culturing with FMNPs. (3) Nude mouse models loaded with gastric cancer were established, and then labeled BMSCs were intravenously injected into these mice. The signals were detected by using Animal Imaging System and Magnetic Resonance Imaging to verify the tropism capability of rat BMSCs for gastric cancer.Results: (1) FACS analysis showed that the passage three BMSCs which were harvested and purified by adherent culture were positive for markers CD29, CD90, CD45 as 84.69%, 90.28% and 0.72%. ALP staining and oil red O staining indicated that BMSCs were inducted into osteoblasts and adipose cells. (2) BMSCs were co-cultured with FMNPs and then tested their survival rate in different periods in order to choose the appropriate labeled concentration, which is 50?g/mL. Prussian blue staining, laser scanning confocal and magnetic resonance imaging showed that the prepared FMNPs successfully labeled BMSCs, and did not affect cell viability.(3) Nude mouse models loaded with gastric cancer were established in four weeks by the means of subcutaneously injecting gastric cancer cells MGC803 into nude mice. Then labeled BMSCs were intravenously injected into these mice via a single tail vein. The signals were detected by using Animal Imaging System after 14 days. Afterwards, we euthanized these mice and collected their important tissues such as tumor, brain, spleen, liver, heart, lung and kidney to perform fluorescence imaging analysis again. In particular, abundant fluorescence was presented in tumor tissues, which showed that labeled cells accumulated in tumor tissues. There was no signal detected in spleen, heart, lung, kidney except liver due to the macrophage of liver would phagocytose foreign body in the course of liver metabolism. Furthermore, we investigated whether the MSCs labeled with FMNPs home to the tumor sites. We monitored the tumor tissues by Magnetic Resonance Imaging (MRI) after intravenously injecting MSCs for 14 days, the tumor presented clear magnetic resonance signal at the 3.0 T magnetic field intensity.Conclusion: (1) It is simple and effective by using adherent culture method to screen out the viable and purified BMSCs. (2) The appropriate concentration of FMNPs can efficiently label BMSCs. (3) BMSCs have highly specific targeted capability for gastric cancer.Signification: The results of our study show that BMSCs have tropism capability for gastric cancer. In addition, BMSCs have the character of collecting convenience, high expansion capacity in vitro, strong gene transfection efficiency, and stable gene expression after transfection and can be autologous transfusion in order to avoid the immune rejection. It is considered as the ideal seed cells for genetic engineering, which provides a theoretical basis for targeted gene therapy of gastric cancer based BMSCs as vectors. However, the molecular mechanism of BMSCs migration to the gastric cancer is not yet clear, and need further studies in near future. |
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