软骨细胞-海藻酸钠水凝胶微球修复大鼠颅骨缺损

Effect of articular chondrocytes combined with sodium alginate hydrogel sphere on rat calvarial defects

目的探讨软骨细胞-海藻酸钠水凝胶修复骨缺损的可行性,比较其与单纯海藻酸钠水凝胶修复效果的差别。方法取SD大鼠乳鼠膝关节软骨分离培养获得第2代软骨细胞,以1×106/m L接种于海藻酸钠水溶液中培养并交联形成复合水凝胶微球。取12只2月龄雄性SD大鼠,建立颅顶单侧缺损模型,随机分为实验组与对照组,分别植入软骨细胞-海藻酸钠水凝胶和单纯海藻酸钠水凝胶微球。于术后6周取材行大体及组织学观察以及Micro-CT扫描定量分析。结果大体观察示术后6周实验组缺损已基本修复完全,表面光滑无塌陷或碎裂,质地较硬接近新生骨组织;对照组缺损明显,周围为不规则骨和纤维结缔样组织。Micro-CT扫描示实验组颅骨缺损得到良好的修复重建,定量分析示实验组骨矿物质密度、骨组织体积分数及骨小梁数目均高于对照组,差异有统计学意义(P<0.05)。组织学观察示术后6周实验组缺损区由新生骨组织修复,含少量软骨及纤维结缔组织,出现血管结构;对照组缺损明显,边缘主要由纤维结缔组织和少量新生骨组织构成。结论海藻酸钠复合软骨细胞制备的水凝胶微球对于大鼠颅骨缺损具有一定的修复效果。

Objective To explore the feasibility of sodium alginate hydrogel with articular chondrocytes in the repair of calvarial defects in rats, and compare its therapeutic effects with simple sodium alginate hydrogel. Methods Chondrocytes were isolated from the knee-joint of Sprague Dawley （SD） rat pups and expanded in vitro, and then the cells of passage 2 （ 1 ×10^6/mL） were inoculated in sodium alginate and crosslinked to be hydrogel sphere. A total of 12 male rats （2 months old） were randomly divided into control and experiment groups. After a circular defect of 5 mm in diameter was inflicted on one side of rat calvarial bone, the composite of chondrocytes and sodiun alginate hydrogel sphere were implanted into the defect in the rats of the experiment group, while only sodium alginate hydrogel sphere were implanted into the defect of the control group. In 6 weeks after operation, all specimens were assessed with general observation, histological analysis and micro-computed tomography （Micro-CT） to evaluate the bone regeneration. Results In 6 weeks after operation, general observation showed that the defects almost have been repaired completely in the experiment group, with the surface smooth without collapses or segments, and hard and dense texture. But the defects were obvious and irregular in the control group, even with fibrous connective tissue around. The Micro-CT showed good repairs and reconstruction of cranial bone in the experiment group, and quantification analysis of relevant parameters showed bone mineral density, bone volume fraction and number of trabecular bones were greater in the exoeriment grouo than the control grouo （ P 〈 0. 05 ）.Histological results showed that the defects in the experiment group were repaired with fresh bone tissues and less cartilage or collagen fibers, even blood capillaries were observed at the same time. The defects of group B were almost vacant with fibrous connective tissues and less bone tissues on the edge. Conclusion The articular chondrocytes combined with sodium alginate hydrngel sphere can reconstruct cranial bone in calvarial defects of SD rats.