RESUMO
BACKGROUND:Stem celltumorigenicity is a practical issue concerning stability in the clinical application of stem cells. Therefore, it is particularly important to clear whether stem cells have tumorigenic ability or not. Nude mice occupy an increasingly important position in oncology, immunology, and safety evaluation of drugs and biological products. OBJECTIVE:To observe the tumorigenicity of neural stem cells and mesenchymal stem cells in Balb/c nude immunodeficient mice. METHODS:Balb/c nude mice were randomly divided into control group, negative group, positive group, neural stem cellgroup and mesenchymal stem cellgroup. HepG-2 cells, RPE cells, passage 4 neural stem cells and mesenchymal stem cells were injected subcutaneously into nude mice from different groups, respectively. After 12 weeks of injection, anatomical observation was performed to detect the tumor formation in the transplantation site. Meanwhile, soft agar colony formation assay was applied to investigate neural stem celland mesenchymal stem cellclone in vitro. RESULTS AND CONCLUSION:After 12 weeks of injection, the tumorigenicity study results showed that no tumor developed in the transplantation site in the control group, negative group, neural stem cellgroup and mesenchymal stem cellgroup. Histopathologic examinations also showed no abnormality in these groups. Soft agar colony formation assay showed in soft agar resistance medium, neural stem cells and mesenchymal stem cells did not exhibit clone ability. These findings indicate that neural stem cells and mesenchymal stem cells undergoing short-term passages have no tumorigenic growth.
