原位递送槲皮素的PECT温敏水凝胶对大鼠脊髓损伤的修复作用

Repair Efficacy of PECT Thermosensitive Hydrogel for in Situ Delivery of Quercetin on Spinal Cord Injury in Rats

目的:探讨负载槲皮素(quercetin,QR)的含环醚侧基聚己内酯-聚乙二醇三嵌段共聚物(PECT)温敏水凝胶对大鼠脊髓损伤(spinal cord injury,SCI)的修复作用。方法:制备负载QR且37℃条件下自动成胶的温敏水凝胶(QR-polycaprolactone-polyglycol triblock,QR-PECT);表征水凝胶的温敏及流变特性;通过CCK-8实验评价水凝胶的细胞相容性;通过1,1-二苯基-2-吡啶并肼基(1,1-diphenyl-2-picrylhydrazyl radical,DPPH)自由基清除实验来评估水凝胶清除自由基的能力;通过活性氧(reactive oxygen species,ROS)检测试剂盒评价水凝胶清除细胞内ROS的能力;制备大鼠SCI全切模型,分为Sham组、SCI组、QR治疗组及QR-PECT水凝胶治疗组,应用BBB评分评估大鼠运动功能的恢复,应用尼氏染色观察神经元迁移浸润情况,通过HE染色评价水凝胶生物相容性。结果:制备的QR-PECT聚合物在37℃条件下形成水凝胶,并持续释放QR;CCK-8实验定量结果显示QR-PECT水凝胶治疗组与SCI组的细胞活力相当;DPPH清除实验显示,QR-PECT水凝胶治疗组的DPPH清除率达到60%,与QR治疗组相当;通过测量HT22细胞内的ROS荧光值,发现QR-PECT水凝胶治疗组的HT22细胞内荧光强度显著降低;SCI后8周,QR-PECT水凝胶治疗组大鼠运动功能明显恢复,尼氏染色显示QR-PECT水凝胶治疗组存在大量神经元浸润,HE染色结果显示QR-PECT水凝胶治疗组心、肝、脾、肺、肾与正常大鼠没有明显的差异。结论:QR-PECT水凝胶具有良好的生物相容性和抗氧化性,并能够促进大鼠SCI后神经元的再生和运动功能恢复。

Objective:To investigate the therapeutic effects of quercetin(QR)-loaded polycaprolactone-polygl ycol triblock(PECT)thermosensitive hydrogel in a rat model of spinal cord injury(SCI).Methods:The thermosensitive hydrogel with QR-PECT was prepared to release quercetin at 37℃.The thermosensitive and rheological properties of the hydrogel were characterized.Cell compatibility of the hydrogel was assessed using the CCK-8 assay.The free radical scavenging ability of the hydrogel was evaluated using the 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)scavenging assay.The ability of the hydrogel to scavenge intracellular reactive oxygen species(ROS)was evaluated using a ROS detection kit.A rat model of SCI was established and divided into four groups:sham,SCI,QR,and QR-PECT hydrogel.The BBB score was used to evaluate the recovery of motor function in the rats.Neuronal migration and infiltration were examined using Nissl staining,and biocompatibility of the hydrogel was assessed by H&E staining.Results:The prepared QR-PECT polymer formed a hydrogel at 37℃and continuously released QR.CCK-8 assay results showed that the cell viability in the QR-PECT hydrogel group was comparable to that of the SCI group.DPPH clearance assays revealed a 60%scavenging rate in the QR-PECT hydrogel group,which was comparable to that of the QR group.ROS fluorescence intensity in HT22 cells indicated a significant reduction after treatment with the QR-PECT hydrogel.Eight weeks after SCI,significant motor function recovery was observed in the QR-PECT hydrogel group,with substantial neuronal infiltration confirmed by Nissl staining.H&E staining revealed no significant differences among heart,liver,spleen,lung,and kidney samples from the normal and QR-PECT hydrogel groups.Conclusion:The QR-PECT hydrogel demonstrated superior biocompatibility and antioxidant characteristics,promoting neuronal regeneration and enhancing motor function recovery in SCI rats.