冰晶重结晶法通过改善衰老软骨细胞浸润促进软骨缺损修复

Ice Crystal Recrystallization Promotes Cartilage Defect Repair by Enhancing Infiltration of Aged Chondrocytes

  • 摘要: 背景 软骨缺损常诱发软骨细胞衰老。现有研究多聚焦于正常软骨细胞在组织工程支架中的浸润,对于衰老软骨细胞浸润的研究尚不充分。目的 探究衰老软骨细胞的浸润能力改变,通过冰晶重结晶技术优化支架结构,改善衰老软骨细胞在支架内的浸润。方法 通过共聚焦显微镜扫描重建法检测衰老软骨细胞与正常软骨细胞在常规冰模板明胶支架中的细胞浸润差异。使用扫描电镜测量支架的孔径与孔隙率。通过单轴压缩实验方法检测支架材料的压缩模量。通过活/死染色方法检测支架材料对衰老软骨细胞的细胞存活率影响。使用CCK-8 法和EdU染色法检测支架材料对衰老软骨细胞的增殖活力影响。使用细胞骨架/细胞核染色方法检测衰老软骨细胞在两类支架中的细胞形态与浸润行为。通过大鼠软骨缺损模型实验评估支架材料在体内促软骨缺损修复的效果。结果 与正常软骨细胞相比,衰老软骨细胞在常规冰模板法明胶支架内的浸润能力减弱(P<0.01)。冰晶重结晶法明胶支架的孔径(21.1±2.7 μm)大于常规冰模板支架(8.0±1.6 μm) (P<0.001),同时拥有更高的孔隙率(P<0.05)。冰晶重结晶支架的压缩模量(16.5±4.5 kPa)高于常规冰模板法(6.2±1.5 kPa) (P<0.05)。活/死染色、CCK-8 实验与EdU染色显示,支架浸提液对细胞活性未产生抑制作用(P>0.05)。观察细胞形态发现冰晶重结晶明胶支架增强了衰老软骨细胞的黏附。培养4 天与14 天后,衰老软骨细胞在冰晶重结晶明胶支架内的浸润深度高于常规冰模板法明胶支架(4 天 132±13.7 μm vs 41±6.2 μm P<0.001) (14 天 1 336.1±80.0 μm vs 929.3±105.0 μm P<0.01)。大鼠软骨缺损模型显示,冰晶重结晶明胶支架促进了大鼠软骨修复(P<0.001)。结论 衰老软骨细胞在明胶支架内浸润能力减弱。冰晶重结晶法制备的新型明胶支架,能够改善衰老软骨细胞的支架浸润,促进软骨缺损修复愈合。

     

    Abstract: Background Cartilage defects often induce chondrocyte senescence. Current research primarily focuses on the infiltration of normal chondrocytes within tissue-engineered scaffolds, with studies on the infiltration of senescent chondrocytes remaining insufficient. Objective To investigate the altered infiltration capacity of senescent chondrocytes and to enhance their infiltration within scaffolds by optimizing scaffold structure via an ice recrystallization technology. Methods The differences in cell infiltration between senescent chondrocytes and normal chondrocytes within conventional ice-templated gelatin scaffolds were examined using confocal microscopy scanning and reconstruction. The pore size and porosity of the scaffolds were measured by scanning electron microscopy. The compressive modulus of the scaffold material was evaluated using a uniaxial compression test. The effect of the scaffold material on the survival rate of senescent chondrocytes was assessed by live/dead staining. The proliferative activity of senescent chondrocytes on the scaffold material was measured using the CCK-8 assay and EdU staining. Cell morphology and infiltration behavior of senescent chondrocytes in the two types of scaffolds were observed via cytoskeleton/nucleus staining. The in vivo effect of the scaffold material on promoting cartilage defect repair was evaluated using a rat cartilage defect model. Results Compared to normal chondrocytes, senescent chondrocytes exhibited a significantly weakened infiltration capacity within conventional ice-templated gelatin scaffolds(P<0.01). The pore size of the gelatin scaffold prepared by the ice crystal recrystallization method (21.1 ± 2.7 μm) was significantly larger than that of the conventional ice-templated scaffold (8.0 ± 1.6 μm) (P<0.001), while also exhibiting higher porosity (P<0.05). The compressive modulus of ice recrystallized scaffolds (16.5 ± 4.5 kPa) was significantly higher than that of conventional ice-templated scaffolds (6.2 ± 1.5 kPa) (P<0.05). Live/Dead staining, CCK-8 assay, and EdU staining indicated that scaffold extracts did not significantly inhibit cell viability (P>0.05). Cell morphology observations showed that the ice recrystallized gelatin scaffold enhanced the adhesion of senescent chondrocytes. After 4 and 14 days of culture, the infiltration depth of senescent chondrocytes was significantly greater in ice recrystallized scaffolds compared to conventional ones (Day 4: 132 ± 13.7 μm vs. 41 ± 6.2 μm, P<0.001; Day 14: 1336.1 ± 80.0 μm vs. 929.3 ± 105.0 μm, P<0.01). The rat cartilage defect model demonstrated that the ice recrystallized gelatin scaffold significantly promoted cartilage repair (P<0.001). Conclusion The infiltration capacity of senescent chondrocytes within gelatin scaffolds is diminished. A novel gelatin scaffold fabricated by the ice recrystallization method can enhance the infiltration of senescent chondrocytes and promote the repair and healing of cartilage defects.

     

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