Effects of Col-Tgel, a bioactive material, on human tissue stem cells / 中国组织工程研究

ABSTRACT

BACKGROUND:The traditional two-dimensional culture system has been widely used in the in vitro culture of human tissue stem cells,but it cannot really simulate the three-dimensional physiological microenvironment in the body, which is not conducive to the study of the biological behavior of human stem cells. OBJECTIVE: To detect the effect of the bioactivity of Col-Tgel in human hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs)in vitro and in vivo,by constructing a three-dimensional culture system stimulating the physiological microenvironment of the body. METHODS:(1)In vitro co-culture:Green fluorescent protein labeled MSCs(MSCs-GFP)and human umbilical cord blood CD34+cells were co-cultured in Col-Tgel for 3 days (three-dimensional culture group). Human umbilical cord blood CD34+cells were cultured in Col-Tgel for 3 days as single culture group. MSCs-GFP and human umbilical cord blood CD34+cells were co-cultured in Transwell chamber for 3 days as two-dimensional culture group. Human umbilical cord blood CD34+cells were cultured routinely as control group. The percentage of CD34+CD38-CD45RA-CD90+cells in each group was measured by flow cytometry. In situ immunofluorescence staining was used to detect the activity of cells that were co-cultured in Col-Tgel.(2)In vivo transplantation:NOD/SCID mice subjected to 24-hour X-ray irradiation were divided into two groups: in experimental group, MSC-GFP cells were resuspended in Col-Tgel and transplanted into the tibia of NOD/SCID mice; in control group, MSCs-GFP were resuspended in PBS and transplanted into the tibia of NOD/SCID mice. The MSC-GFP growth in the bone marrow was detected by two-photon/confocal microscopy at 3 days post transplantation. RESULTS AND CONCLUSION: (1) After co-culture in Col-Tgel for 3 days, the percentage of CD34+CD38-CD45RA-CD90+cells in the three-dimensional culture group was 2.8 times that of the two-dimensional culture group, indicating that the MSCs significantly promoted the expansion of CD34+CD38-CD45RA-CD90+cells in the Col-Tgel. The percentage of CD34+CD38-CD45RA-CD90+cells in the three-dimensional culture group was increased by 4.5 times compared with the single culture group and increased by 1.5 times compared with the control group. Immunofluorescence staining showed that the cell viability of human MSCs and human umbilical cord blood CD34+cells was not affected after co-cultured in Col-Tgel for 3 days.In the in vivo transplantation experiment,MSC-GFP cells could survive in the medullary cavity.In summary, Col-Tgel provides a new strategy for stem cell culture and in vivo growth by forming a three-dimensional system similar to the physiological environment in vivo.