Culture and identification of rabbit marrow stromal cells invitro / 中国组织工程研究

ABSTRACT

BACKGROUND: The study of isolation, purification, culture, cell labeling, inducing factors, effects of gene transfection on cytobiology, cell carrier construction, and time window for back transplantation of cell compound pertaining to marrow stromal cells (MSCs) is still in its infancy. OBJECTIVE: To search for an in vitro culture method that can be simply and effectively obtained. DESIGN, TIME AND SETTING: The present cytological in vitro experiment was performed at the Beijing Institute of Genome, Chinese Academy of Sciences between June 2006 and July 2007. MATERIALS Eight specific pathogen-free New Zealand rabbits, aged 6 weeks, were provided by the Laboratory Animal Center, Institute of Genetics and Development, Chinese Academy of Sciences. METHODS: Under sterile condition, 1 mL rabbit bone marrow was taken and diluted with D-Hanks solution. Following centrifugation and subsequent supernatant removal, bone marrow was re-suspended using dulbecco's modified eagle's medium (DMEM) for single cell suspension. Next, single cell suspension was dropped onto the liquid surface of equal-volume lymphocyte separation medium (density 1.077). Subsequent to centrifugation, cloudlike mononuclear cell layer was collected and re-suspended with DMEM containing 20% fetal bovine serum. The cells were inoculated at lxl0/cm2 and purified by adherent method. When 70%-80% of flask bottom was covered, cell digestion and passage was performed.MAIN OUTCOME MEASURES: Cell growth was observed with an operating microscope. Surviving cells were counted by Trypan blue viability test. Cell identification was performed by hematoxylin-eosin staining. Through the use of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, cell viability was detected to observe the cellular resuscitation of the cultured cells following cryopreservation. RESULTS: Twenty-four hours after inoculation, cells began to adhere to the wall, exhibiting short shuttle- or triangle-shaped appearance with different sizes of cellular processes. Three days later, adherent cells began to divide, and cell clusters could be found in some areas; One week later, most of cells exhibited scattered fibroblast-like growth; After passage, cells were evenly distributed with long shuttle-shaped appearance and arranged orderly. Following 3 passages, there wound be 5×106-1×107 adherent cells in 1 mL MSC suspension. Approximately 90% of MSCs survived and identified as mononuclear cells. Cells vigorously grew at days 1-6 after inoculation and reached a peak level at day 8, followed by a viability decline. After 56 days of resuscitation, frozen cells displayed a good and rapid growth. CONCLUSION: Highly purified MSCs can be acquired by gradient centrifugation of lymphocyte separation medium. Enough seeded cells can be obtained by in vitro culture and the cellular viability does not change after frozen preservation and resuscitation.