不同浓度BMSCs联合壳聚糖导管对大鼠全横断脊髓损伤修复作用的比较

Comparison Study of Effect of Chitosan Conduit Combine with BMSCs in Different Density on Complete Spinal Cord Transection of Rat Repair

比较不同浓度的骨髓基质干细胞(BMSCs)联合壳聚糖导管移植物在大鼠脊髓全横断损伤模型中的修复作用。体外分离培养大鼠BMSCs,分别以104/mL(A组)、106/mL(B组)和108/mL(C组)的浓度联合壳聚糖导管植入大鼠T8全横断脊髓损伤模型中;术后12周电生理检测结果显示各组大鼠在大脑皮层、损伤平面以下刺激时均能在腓肠肌内记录到运动诱发电位,其中皮层潜伏期C组短于A组,皮层振幅B、C组大于A组(P<0.05);取材后大体观察各组移植物均能和损伤脊髓两端整合良好;尼氏染色显示在再生区域中段神经元数目C组大于A、B组(P<0.05);双重免疫荧光组织化学检测显示再生轴突能穿越胶质瘢痕界面长入损伤远端;电镜观察再生区域内有较多的有髓神经纤维,其中C组的有髓神经数目多于A组,髓鞘厚度大于A、B组(P<0.05)。BMSCs联合壳聚糖导管制成的人工组织移植物可以桥接脊髓损伤造成的缺损,部分恢复电生理特性,促进轴突再生,其中高浓度细胞组(C组)修复效果较好,提示该移植方法可为脊髓损伤的治疗提供新思路。

The aim of this study is to compare the effect of chitosan conduit combine with bone marrow stromal cells （BMSCs） in different density on complete spinal cord transection of rat repair. BMSCs of rat were isolated and cultured in vitro and then transplanted into complete spinal cord transection at T8 of rat combine with chitosan conduit in density of 104/mL （group A） , 106/mL （group B） and 10S/mL （group C）. Twelve weeks later, the electrophysiological assessment showed that motor evoked potentials could be recorded on the gastrocnemius muscle by stimulation on either of the cerebral cortex or lower injured site in all groups. The latency period of the cerebral cortex in group C was significantly shorter than that in group A, and the amplitude of the cerebral cortex in groups B and C was higher than that in group A （P 〈 O. 05）. Gross observation showed the transplants can connect the stumps across the gap in the spinal cord. Nissl＇s staining showed the number of neurons at the mid-portion of the regenerated tissue in group C was bigger than that in groups A and B （P 〈 0. 05）. Double fluorescence immunohistochemistry study showed the regenerated axons could cross the glial scar and migrated to the distal stump. Transmission electron microscopy of the regenerated tissue showed many regenerated myelinated nerve fibers. The number of myelinated nerve fibers in group C was bigger than that in group A, and myelin sheathes in group C were thicker than groups A and B （P 〈 0. 05）. The syntheticgrafts composed of BMSCs and chitosan conduit can bridge the damage caused by spinal cord injury, make electrophysiological characteristics recovery to a certain degree, and promote regeneration of axons. Among all groups, group C with high density of BMSCs provide better repairing effect, suggesting that implantation may become a promising approach to the repair of spinal cord injury.