多孔丝素蛋白/羟基磷灰石复合脂肪间充质干细胞修复兔关节软骨及软骨下骨缺损

Repair of rabbit articular cartilage and subchondral defects using porous silk fibroin/hydroxyapatite combined with adipose-derived stromal cells

背景:丝素蛋白/羟基磷灰石是细胞立体培养的良好支架,是临床常用的骨缺损修复材料,具有良好的生物相容性。脂肪干细胞具有向骨及软骨细胞分化的潜能,适合骨软骨缺损修复。目的:观察转化生长因子β1和胰岛素样生长因子1联合成软骨诱导脂肪干细胞与丝素蛋白/羟基磷灰石复合后修复兔关节软骨及软骨下骨缺损的效果。方法:取新西兰大白兔56只,2只用于传代培养脂肪间充质干细胞,以3×109L-1浓度接种到丝素蛋白/羟基磷灰石。其余54只新西兰大白兔,在股骨髁间制备软骨缺损模型,随机分为细胞复合材料组、单纯材料组和空白对照组,细胞复合材料组植入复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石;单纯材料组植入丝素蛋白/羟基磷灰石;空白对照组不作任何植入。从大体、影像学、组织学观察比较缺损的修复情况。结果与结论:12周时大体观察、CT、磁共振和组织学检查细胞材料复合组软骨及软骨下骨缺损区完全被软骨组织修复,修复组织与周围软骨色泽相近,支架材料基本吸收,未见明显退变和白细胞浸润,所有标本均未见丝素蛋白残留。单纯材料组缺损区缩小、部分修复,且呈纤维软骨样修复。空白对照组缺损无明显修复。提示复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石修复兔关节软骨及软骨下骨缺损能力优于单纯丝素蛋白/羟基磷灰石材料。丝素蛋白/羟基磷灰石复合脂肪间充质干细胞可形成透明软骨修复动物膝关节全层软骨缺损,重建关节的解剖结构和功能,可作为新型骨软骨组织工程支架。

BACKGROUND： Silk fibroin/hydroxyapatite （SF/HA） is a good scaffold for three-dimensional culture of cells, and is a common material to repair bone defect with good biocompatibility. Adipose-derived stem cells （ADSCs） which can differentiate into bone and cartilage cells are ideal for repairing cartilage defect. OBJECTIVE： To observe the effects of the repair of articular cartilage and subchondral defects in rabbit knee joints with transforming growth factor-β1 and insulin like growth factor-1 in combination with SF/HA and ADSCs. METHODS： A total of 56 New Zealand rabbits were selected, and 2 were used for cultures of ADSCs, which were seeded onto SF/HA at a concentration of 3×109/L. The remaining 54 rabbits were used to establish model of articular cartilage and subchondral defects and randomly assigned to composite, simple and blank control groups. The composite and simple groups were respectively implanted with SF/HA/ADSCs scaffold and SF/HA scaffold. The blank control group was not implanted any materials. Repair of defects was observed and compared by gross, imaging and histological observations. RESULTS AND CONCLUSION： At 12 weeks, gross observation, CT, MRI and histological observations demonstrated that the articular cartilage and subchondral defects were repaired entirely in composite group. The color of repaired tissues was similar to surrounding cartilage. There was no evidence of the residue of silk fibroin or the infiltration of leukocytes. Defects were repaired partially and repaired with cartilage fibrosa in simple group. However, defects remained unchanged in blank control group. Results showed that SF/HA with ADSCs composite could successfully repair articular cartilage and subchondral defects of a rabbit knee joints and the effect was superior to SF/HA scaffold alone. The method for repairing the full-thickness hyaline cartilage defects and reconstructing anatomical structure and function of joints using SF/HA with ADSCs is feasible and promising to serve as a new biomaterial of osteochondral tissue engineering.