Emin Nuray, Koç Aysel, Durkut Serap, Elçin A Eser, Elçin Y Murat
Ankara University, Faculty of Science and Biotechnology Institute, Tissue Engineering and Biomaterials Laboratory, Ankara, Turkey.
Artif Cells Blood Substit Immobil Biotechnol. 2008;36(2):123-37. doi: 10.1080/10731190801932116.
The objective of this study was to develop an engineered rat hyaline cartilage by culturing articular chondrocytes on three-dimensional (3D) macroporous poly(DL-lactic-co-glycolic acid) (PLGA) sponges under chondrogenic induction and microgravity bioreactor conditions. Experimental groups consisted of 3D static and dynamic cultures, while a single cell monolayer (2D) served as the control. The effect of seeding conditions (static vs. dynamic) on cellularization of the scaffolds was investigated. MTT assay was used to evaluate the number of viable cells in each group at different time points. Formation of a hyaline-like cartilage was evaluated for up to 4 weeks in vitro. While 2D culture resulted in cell sheets with very poor matrix production, 3D culture was in the favor of tissue formation. A higher yield of cell attachment and spatially uniform cell distribution was achieved when dynamic seeding technique was used. Dynamic culture promoted cell growth and infiltration throughout the sponge structure and showed the formation of cartilage tissue, while chondrogenesis appeared attenuated more towards the outer region of the constructs in the static culture group. Medium supplemented with TGF-beta 1 (5 ng/ml) had a positive impact on proteoglycan production as confirmed by histochemical analyses with Alcian blue and Safranin-O stainings. Formation of hyaline-like tissue was demonstrated by immunohistochemistry performed with antibodies against type II collagen and aggrecan. SEM confirmed higher level of cellularization and cartilage tissue formation in bioreactor cultures induced by TGF-beta 1. The data suggest that PLGA sponge inside rotating bioreactor with chondrogenic medium provides an environment that mediates isolated rat chondrocytes to redifferentiate and form hyaline-like rat cartilage, in vitro.
本研究的目的是通过在三维(3D)大孔聚(DL-乳酸-乙醇酸)(PLGA)海绵上培养关节软骨细胞,并在软骨形成诱导和微重力生物反应器条件下,构建工程化大鼠透明软骨。实验组包括3D静态和动态培养,而单细胞单层(2D)作为对照。研究了接种条件(静态与动态)对支架细胞化的影响。采用MTT法评估不同时间点每组活细胞数量。在体外长达4周的时间内评估类透明软骨的形成。2D培养导致细胞片层产生的基质非常少,而3D培养有利于组织形成。采用动态接种技术时,细胞附着率更高,细胞分布在空间上更均匀。动态培养促进细胞生长并渗透到整个海绵结构中,并显示出软骨组织的形成,而在静态培养组中,软骨形成在构建体的外部区域似乎更减弱。补充有TGF-β1(5 ng/ml)的培养基对蛋白聚糖的产生有积极影响,这通过阿尔新蓝和番红O染色的组织化学分析得到证实。用抗II型胶原和聚集蛋白聚糖的抗体进行免疫组织化学,证实了类透明组织的形成。扫描电子显微镜(SEM)证实,在TGF-β1诱导的生物反应器培养中,细胞化水平更高,软骨组织形成更好。数据表明,在旋转生物反应器中加入软骨形成培养基的PLGA海绵提供了一种环境,可介导分离的大鼠软骨细胞在体外重新分化并形成类透明大鼠软骨。