聚乙烯醇/壳聚糖多孔水凝胶复合骨髓间充质干细胞修复膝关节软骨缺损

Repair of articular cartilage defects with polyvinyl alcohol/chitosan porous hydrogel combined with bone marrow mesenchymal stem cells

背景:混合技术可增强材料的热敏性、机械性能、黏弹性和结构性能,还可改善混合材料的生物降解性、生物相容性和其他生物医学性质。目的:制备聚乙烯醇/壳聚糖多孔水凝胶材料,观察其修复软骨缺损的效果。方法:在加入与不加入表面活性剂聚山梨酯80的情况下,通过冷冻-解冻循环及乳化发泡-冷冻冰晶相分离法制备不同组分的聚乙烯醇/壳聚糖多孔水凝胶材料(聚乙烯醇与壳聚糖的质量比分别为5∶5、6∶4、7∶3、8∶2及9∶1),以含水率、溶胀度、热行为、力学性能及细胞相容性实验筛选聚乙烯醇与壳聚糖最佳质量比,进行动物体内实验。取18只新西兰大白兔,制作双侧膝关节软骨缺损模型,随机分3组干预,实验组缺损处植入负载骨髓间充质干细胞的聚乙烯醇/壳聚糖多孔水凝胶材料,对照组植入聚乙烯醇/壳聚糖水凝胶,空白对照组未植入任何材料,植入12周后,组织学观察修复效果。结果与结论:(1)成功制备了聚乙烯醇/壳聚糖多孔复合水凝胶,以加入聚山梨酯80、聚乙烯醇与壳聚糖质量比为6∶4的水凝胶含水量≥90%,力学性能良好,理化性能稳定,孔隙率≥90%,内部疏松多孔的网状结构更利于细胞生长增殖,具有良好细胞相容性,选择其进行动物体内植入实验;(2)空白对照组软骨缺陷完全没有再生,表面只有一层薄薄的纤维覆盖;对照组软骨缺陷由类软骨组织填充,表面欠光滑,填充不完整,但可见大量类软骨细胞长入;实验组修复效果最好,表面平整,由大量细胞填充;(3)结果表明,复合骨髓间充质干细胞的聚乙烯醇/壳聚糖多孔水凝胶材料可促进软骨缺损的修复。

BACKGROUND： By mixing technology, various materials are mixed and complemented each other to enhance heat sensitivity, mechanical properties, viscoelasticity of the materials and improve their biocompatibility, biodegradability and other biomedical properties. OBJECTIVE： To prepare polyvinyl alcohol（PVA）/chitosan（CS） porous hydrogel and to observe its effects on the repair of articular cartilage defects. METHODS： PVA, CS and polysorbate-80 were used as raw materials to prepare the hydrogels at the PVA/CS ratio of 5：5, 6：4, 7：3, 8：2 and 9：1 by freezing-thawing cycle and emulsification-frost-ice phase separation, and the physical and chemical properties, mechanical properties, and biocompatibility of the hydrogels were detected to find out the best PVA/CS ratio. Eighteen New Zealand rabbits were enrolled to make models of bilateral articular cartilage defects, and then randomized into three groups： blank control group; control group; experimental group. The prepared hydrogel was compounded with rabbit bone marrow mesenchymal stem cells（BMSCs） and then implanted into the rabbit articular cartilage defect in the experimental group, the PVA/CS hydrogel was implanted in the control group, and nothing was implanted in the blank control group. After 12 weeks, the animals were killed and the repairing effect was observed by gross observation and histological examination. RESULTS AND CONCLUSION： The PVA/CS porous composite hydrogel was successfully prepared, and PVA：CS=6：4 was the best in the presence of good mechanical properties, stable physical and chemical properties, and water content ≥ 90%. In additional, scanning electron microscopy showed a porous network structure, with the porosity ≥ 90%. The results of cell counting kit-8 assay and the results of cell death and survival showed that the hydrogel was non-cytotoxic and beneficial to the cell proliferation. In the blank control group, knee articular cartilage defects were not repaired within 12 weeks after surgery, showing significant granulation tissue filling. In the control group, knee articular cartilage defects were full of cartilage-like tissues with no smooth surface, but there were a great amount of chondrocyte-like cells. In the experimental group, knee articular cartilage defects were well repaired and full of a great amount of chondrocytes with the smooth surface. To conclude, the PVA/CS porous composite hydrogel could repair articular cartilage defects as an ideal tissue-engineered cartilage material.