改良体外培养方法及诱导剂配比条件下骨髓间充质干细胞向成骨细胞的分化

背景:骨髓间充质干细胞取材方便,易于体外扩增,其体外培养方法及诱导分化仍需要改良.目的:对大鼠骨髓间充质干细胞体外培养方法及诱导剂配比进行改良,观察骨髓间充质干细胞向成骨细胞分化的潜能.设计:观察实验.单位:解放军广州军区广州总医院医学实验科.材料:实验于2004-07/2006-06在解放军广州军区总医院医学实验科干细胞组织工程实验室完成,选用20只成年SD大鼠,清洁级,雌雄不拘,体质量140～180 g,由解放军广州军区广州总医院动物实验中心提供.实验过程中对动物的处置符合动物伦理学标准.β-甘油磷酸纳,地塞米松,维生素C均为美国Sigma公司产品,羊抗大鼠骨钙素抗体购自美国DSL公司,S-P免疫组化试剂盒为福建迈新生物技术开发有限公司产品.方法:采用改良法进行细胞的培养及诱导细胞成骨.①骨髓间充质干细胞分离及培养:大鼠麻醉后处死分离双侧股骨、胫骨骨髓制备单细胞悬液接种于培养瓶中,培养后48及96 h半量更换培养液,以去除未贴壁的造血细胞,以后每3 d换液1次,进一步去除未贴壁的细胞,待细胞汇合约80%时,用0.25%胰蛋白酶消化,按1:2传代培养.将第2代骨髓间充质干细胞接种于6孔培养板和玻璃平皿中,48 h后吸去基础培养液.②骨髓间充质干细胞向成骨细胞诱导分化:应用含终浓度分别为10 mmol/L、10-7 mol/L、50 mg/L的地塞米松、β-甘油磷酸纳和维生素C的诱导分化培养液定向诱导传代细胞向成骨细胞分化.主要观察指标:①应用改良的培养方法及自行配比的培养液诱导分化后10 d采用钙钴法测定碱性磷酸酶活性.②培养后12 d采用免疫组织化学法检测骨钙素分泌情况.③诱导培养后2周采用Von kossa染色检测细胞矿化作用.结果:①碱性磷酸酶活性:经诱导后细胞碱性磷酸酶染色明显,胞质中刚性反应呈现灰黑色颗粒或块状沉淀,碱性磷酸酶活性部位呈棕黑色.②骨钙素分泌情况:细胞经诱导后骨钙素阳性较明显,胞核呈蓝色,胞浆呈棕色.③细胞矿化作用:细胞经诱导培养后呈复层生长,并出现不透明结节,Von kossa染色可见黑色的矿化结节颗粒,颗粒大小不均一,提示有矿化基质沉积.结论:改良法可成功培养及诱导大鼠骨髓间充质干细胞成骨.

Differentiation of bone marrow mesenchymal stem cells into osteoblasts by modified in vitro culture methods and inductor matching

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) are in advantages of easy collection and amplification in vitro, but the culture and induction in vitro still need to be modified. OBJECTIVE: To investigate the differentiated potency of BMSCs into ostcoblasts by modified in vitro culture methods and inductor matching. DESIGN: Observational study. SETTING: Department of Medical Laboratory, General Hospital of Guangzhou Military Area Command of Chinese PLA. MATERIALS: This study was performed in the Stem Cell Tissue Engineering Laboratory, Department of Medical Laboratory, Genera Hospital of Guangzhou Military Area Command of Chinese PLA from July 2004 to June 2006. Twenty adult SD rats of clean grade, irrespective of gender, weighing 140-180 g were provided by Animal Experimental Center, General Hospital of Guangzhou Military Area Command of Chinese PLA. The experimental animals were disposed according to ethical criteria. Β-sodium glycerophosphate, dexamethasone, and vitamin C were provided by Sigma Company, USA; goat-anti-rat osteocalcin antibody by DSL Company, USA; S-P immunohistochemical kit by Maixin Biotechnology Developing Co., Ltd., Fujian. METHODS: Cells were cultured and induced into osteoblasts by modified methods. Separation and culture of BMSCs: By anesthesia, bone marrow of bilateral femur and tibia was separated to prepare single cell suspension; subsequently, the suspension was inoculated in culture bottle, and the culture media was semi-quantitatively changed after 48 and 96 hours in order to get rid of non-adherent hematopoietic cells. The liquid was changed every three days to further get rid of non-adherent cells. At 80% cell confluence, the medium was digested with 0.25% trypsin and cells were subcultured in the ratio of 1:2. MSCs in the second generation were inoculated in 6-well culture plate and glass fiat plate; after 48 hours, basic culture fluid was removed. Differentiation of BMSCs into osteoblasts: Subcultured BMSCs differentiated into osteoblasts induced by dexamethasone (10 mmol/L), β-sodium glycerophosphate (10-7 mol/L), and vitamin C (50 mg/L). MAIN OUTCOME MEASURES: Ten days after differentiation by modified culture methods and inductor matching, alkaline phosphatase activity was measured with Ca-Co technique. Twelve days after culture, osteocalcin secretion was detected with immunohistochemical method. Two weeks after culture, cell mineralization was detected with Von kossa staining. RESULTS: Alkaline phosphatase activity: Alkaline phosphatase staining of cells was apparent; gray-black particles or massive precipitations were observed in cytoplasm after positive reaction; regions expressing alkaline phosphatase activity were brown-black. Osteocalcin secretion: Osteocalcin was apparently positive; nucleus was blue; cytoplasm was brown. Cell mineralization: Induced cells grew layer by layer, and adiaphanous nodus was observed at the same time. Black mineralized nodus granules in various sizes were observed after Von kossa staining, and this suggested that mineralized apposition occurred. CONCLUSION: BMSCs may be successfully cultured and induced into osteoblasts by modified culture method.