应用密度梯度离心和贴壁筛选法分离免骨髓间充质干细胞

背景:特定条件下,骨髓间充质干细胞可向成骨细胞、成软骨细胞等细胞分化.但骨髓中间充质干细胞含量极低,体外如何获取、纯化并使其高效快速增殖是组织工程技术应用和推广的前提.目的:优化获取兔骨髓间充质干细胞并对其进行纯化、鉴定,同时对其生物学性状进行观察.设计、时间和地点:观察性实验,于2005-09/2006-07在同济医学院实验动物中心完成.材料:兔龄2个月雌性新西兰纯种大耳白兔1只,用于间充质干细胞取材及原代培养.方法:采用密度梯度离心法、贴壁筛选法并结合传代对抽取的骨髓液进行纯化.首先将培养瓶中的培养液吸出,加PBS后再加入2.5 g/L胰酶约3.0 mL,置于37℃培养箱中,两三分钟后在倒置显微镜下观察细胞形态,当细胞胞质回缩,细胞变瘦长,细胞间隙增大,同时有少量脱肇的圆形细胞时可终止消化,加入含血清的L-DMEM完全培养基即可.按1.0X 108L-1的密度接种到一次性塑料培养瓶中进行培养.主要观察指标:间充质干细胞的形态、超微结构和表面标志物的表达;第1,3,5,8,10代细胞的增殖情况,并绘制出生长曲线.结果:①经密度梯度离心法、贴壁筛选法并结合传代方法所得的间充质干细胞很纯,第3代和第5代细胞形态单一,细胞排列具有典型的漩涡状结构.②透射电镜观察显示间充质干细胞核大,以圆形或类圆形为主,胞核比例大,细胞器少,为低分化细胞.③传代培养的间充质干细胞生长曲线呈S型,第1,3,5代细胞增殖能力强,细胞生长旺盛,而第8,10代细胞增殖明显减弱.④所分离培养的细胞表达CD44、CD90,不表达CD34,电镜观察为低分化细胞.结论:分离培养的细胞为间充质干细胞且成分单一,具有干细胞特性,第3代和第5代细胞很纯且其增殖能力强.

Isolation of rabbit bone marrow mesenchymal stem cells using density gradient centrifugation and adherence screening methods

BACKGROUND: Under special conditions, bone marrow mesenchymal stem cells (BMSCs) can differentiate into osteoblasts and chondroblasts. However, MSCs are few in bone marrow. How to harvest, purity and rapidly proliferate in vitro is a foundation of application in tissue engineering technique. OBJECTIVE: To optimize, collect, purity, assess rabbit BMSCs and to observe the biological character of BMSCs. DESIGN, TIME AND SETTING: The observational study was performed at the Animal Experimental Center of Tongji Medical College from September 2005 to July 2006. MATERIALS: One female New Zealand rabbits aged 2 months were used for MSC collection and primary culture. METHODS: Bone marrow solution was purified by density gradient centrifugation and adherence screening method. Culture solution was obtained. BMSCs were incubated in phosphate buffered solution (PBS), supplemented with 2.5 g/L trypsin (3.0 mL), and placed in an incubator at 37 ℃ for two or three minutes. Cell morphology was observed using an inverted microscope. The digestion was stopped when cytoplasm recovery, long and thin cells with large intercellular space, and few round cells appeared. Subsequently, BMSCs were incubated in serum-free L-DMEM, and placed in a plastic culture flask at 1.0×108/L. MAIN OUTCOME MEASURES: MSC morphology, ultrastructura and surface marker; Proliferation of the first, third, fifth, eighth and tenth passages of BMSCs; Cell growth curve was drawn. RESULTS: BMSCs was pure following density gradient centrifugation and adherence screening method. The third and fifth passage of cells had typical whirlpool-shape. Transmission electron microscope demonstrated that round or oval MSCs possessed large nuclei, big nucleus proportion, a few cellular organ. These were low-differentiated cells. Growth curve of cultured MSCs was "S" shape. The first, third and fifth passage cells had strong reproductive capability. The eighth and tenth passage of cells had significantly reduced proliferation. Cells isolated were positive for CD44 and CD90, but negative for CD34. These were low-differentiated cells under the electron microscope. CONCLUSION: Isolated cells are MSCs, with the property of stem cells. The third and fifth passage cells are pure, with strong reproductive capability.