Cai Xiaoxiao, Lin Yunfeng, Ou Guomin, Luo En, Man Yi, Yuan Quan, Gong Ping
Dental Implant Center, West China College of Stomatology, Sichuan University, No. 14, 3rd Sec, Ren Min Nan Road, Chengdu 610041, Sichuan, PR China.
Cell Biol Int. 2007 Aug;31(8):776-83. doi: 10.1016/j.cellbi.2007.01.011. Epub 2007 Jan 21.
In orthopedics, the regeneration and repair of cartilage or bone defects after trauma, cancer, or metabolic disorders is still a major clinical challenge. Through developmental plasticity, bone marrow mesenchymal stem cells (BMSSCs) are important seed cells for the musculoskeletal tissue engineering approach. The present study sought to determine the ectopic osteogenic and chondrogenic ability of BMSSCs in combination with a scaffolding material made from alginate gel. After isolation from the bone marrow of BALB/C mice, BMSSCs were expanded in vitro and induced to chondrogenesis or osteogenesis for 14 days, respectively. Subsequently, these induced cells were seeded into alginate gel, and the constructs implanted into BALB/C nude mice subcutaneously for up to 8 weeks. In the histological analysis, the transmission electron microscopy of the retrieved specimens at various intervals showed obvious trends of ectopic cartilage or bone formation along with the alteration of the cellular phenotype. Simultaneously, the results of the immunohistochemical staining and RT-PCR both confirmed the expression of specific extracellular matrix (ECM) markers for cartilaginous tissue, such as collagen type II (Col-II), SOX9, and aggrecan, or alternatively, markers for osteoid tissue, such as osteopontin (OPN), osteocalcin (OCN), and collagen type I (Col-I). During subcutaneous implantation, the elevating production of ECM and the initiation of the characteristic structure were closely correlated with the increase of time. In contrast, there was an apparent degradation and resorption of the scaffolding material in blank controls, but with no newly formed tissues. Finally, the constructs that were made of non-induced BMSSCs nearly disappeared during the 8 weeks after implantation. Therefore, it is suggested that alginate gel, which is combined with BMSSCs undergoing differentiation into skeletal lineages, may represent a useful strategy for the clinical reconstruction of bone and cartilage defects.
在骨科领域，创伤、癌症或代谢紊乱后软骨或骨缺损的再生与修复仍是一项重大的临床挑战。通过发育可塑性，骨髓间充质干细胞（BMSSCs）是肌肉骨骼组织工程方法的重要种子细胞。本研究旨在确定BMSSCs与藻酸盐凝胶制成的支架材料相结合的异位成骨和成软骨能力。从BALB/C小鼠的骨髓中分离出BMSSCs后，在体外进行扩增，并分别诱导其成软骨或成骨14天。随后，将这些诱导细胞接种到藻酸盐凝胶中，并将构建体皮下植入BALB/C裸鼠体内长达8周。在组织学分析中，对不同时间间隔取回的标本进行透射电子显微镜检查，结果显示随着细胞表型的改变，出现了明显的异位软骨或骨形成趋势。同时，免疫组织化学染色和逆转录聚合酶链反应（RT-PCR）的结果均证实了软骨组织特异性细胞外基质（ECM）标志物的表达，如II型胶原（Col-II）、SRY-box转录因子9（SOX9）和聚集蛋白聚糖，或者类骨组织标志物的表达，如骨桥蛋白（OPN）、骨钙素（OCN）和I型胶原（Col-I）。在皮下植入过程中，ECM产量的增加和特征性结构的形成与时间的增加密切相关。相比之下，空白对照组的支架材料出现明显降解和吸收，但没有新形成的组织。最后，由未诱导的BMSSCs制成的构建体在植入后8周内几乎消失。因此，有人提出，藻酸盐凝胶与分化为骨骼谱系的BMSSCs相结合，可能是临床重建骨和软骨缺损的一种有用策略。
