微载体/水凝胶复合支架修复大鼠膝关节骨软骨缺损

Microcarrier / hydrogel composite scaffold for repair of articular cartilage defect in rat

[目的]探索以负载软骨细胞的Cytodex-3微载体和藻酸钠水凝胶为材料,制备微载体/水凝胶复合支架,并观察以此修复大鼠膝关节骨软骨缺损的效果。[方法]将大鼠软骨细胞与Cytodex-3微载体置于旋转式三维生物反应器(rotary cell culture systems,RCCS)中,软骨细胞在微载体表面快速大量扩增后,将负载有软骨细胞的微载体均匀的与藻酸钠水凝胶混合,制备微载体/水凝胶复合支架,并以此修复大鼠股骨滑车骨软骨缺损。实验分3组,A组:负载有软骨细胞的Cytodex-3微载体/藻酸钠水凝胶复合支架修复组;B组:单纯Cytodex-3微载体/藻酸钠水凝胶复合支架修复组;C组:空白对照组。术后6、12周取材,据大体、组织学、Micro-CT等检测结果对骨软骨修复效果进行评估。[结果]大体观显示A组的软骨修复效果明显优于B组和C组。组织学分析示A组的修复组织主要以透明软骨为主,而B组和C组主要以纤维组织为主。Micro-CT扫描结果表明各种软骨下骨均得到不同程度的重建,A组效果优于其他两组,比较差异有统计学意义。[结论]负载软骨细胞的微载体/藻酸钠水凝胶复合支架能够高效的修复大鼠股骨滑车骨软骨缺损,这种将微载体与水凝胶结合构建复合支架的方法,为组织工程软骨的制备提供了新的途径。

[Objective] To investigate the effect of chondrocyte- seeded Cytodex- 3 microcarrier / alginate hydrogel composite scaffold for articular cartilage repair in a rat model. [Method]Rat chondrocytes and Cytodext- 3 microcarriers were co-cultured in a rotary cell culture system（ RCCS）. Chondrocytes were attached to the surface of microcarrier and proliferated rapidly on microcarrier. Then the chondrocyte- seeded microcarrier and alginate hydrogel were mixed in a cylindrical mould to form a microcarrier / hydrogel composite scaffold. The composite scaffold was then used for in vivo articular cartilage repair. Animal experiment was divided into three groups. In group A,cartilage defect was treated with chondrocyte- seeded microcarrier / hydrogel composite scaffold. In group B,cartilage defect was treated with only microcarrier / hydrogel scaffold,and group C was prepared as the blank control group. At 6,12 weeks after surgery,gross observation,histological evaluation,and Micro- CT scanning were conducted to evaluate the cartilage repair effects. [Result]Gross observation revealed that defect in group A had achieved the best effect of cartilage repair,compared to the results of two other groups. Histological evaluation showed that in group A,repaired tissue consisted of more and thicker hyaline- like cartilage tissue,and possessed more intense Safranin O staining. While in group B,only formation of fibrocartilage was found to repair tissue. Micro- CT scanning results also indicated that there was more mineralized bone formation in group A than the results of the other two groups. [Conclusion]Chondrocyte- seeded micro-carrier / hydrogel composite scaffold can repair rat articular cartilage effectively,and this strategy of constructing scaffold with microcarrier and hydrogel provides novel prospects for cartilage tissue engineering and may have further broad clinical applications.