Chondroitinase对成年大鼠脊髓完全性横断损伤后胶质瘢痕的影响

目的研究Chondroitinase(chABC)对成年大鼠脊髓完全性横断性损伤(spinal cord injury,SCI)后胶质瘢痕及纤维浸润的长期影响。方法 Wistar大鼠24只,在第10胸段脊髓(T10)给予破坏脊膜的完全性横切术,然后随机分为2组,在SCI处分别给予chABC或生理盐水。14周后,脊髓横断从胸9至胸11(10mm组织块)连续切片,首先用Trichrome组织学染色切片确定SCI中心及距中心头侧和尾侧各500μm位置,Trichrome染色和免疫组织化学染色测量损伤脊髓中胶原蛋白浸润的面积,硫酸软骨素蛋白聚糖(CSPGs)的免疫反应强度。免疫荧光共聚焦显微成像检测pCREB(1:25)和GFAP表达,以及测量在SCI处纵向的最短GFAP阴性距离。结果应用chABC治疗可降低脊髓完全性横断后结缔组织的浸润。在SCI处胶原蛋白的纵向最大浸润距离以及在脊髓横断切片上的浸润面积,在chABC组显著减小(p0.05)。在SCI处纵向的最短GFAP平均阴性距离在chABC组中显著低于未治疗组(p0.05),表明更多的剩余正常组织在SCI后得以保留。chABC还能有效地清除轴突再生的抑制因子CSPGs(p0.05)。结论 Chondroitinase通过减少纤维浸润和胶质瘢痕以及清除抑制性细胞外基质分子CSPGs,可为脊髓损伤后神经功能恢复和轴突再生提供有利的局部环境。

Effect of chondroitinase treatment on the glial scar after complete spinal cord transection in adult rats

Objective To study the long term effect of chondroitinase treatment on the glial scar and the infiltration of connective tissue after complete spinal cord transection（SCI） in adult rats. Methods Wistar rats （24） were completely transected at TIO and received chABC （10 μL, 2.5 units/ml and dorsally in gelfoam） or normal saline at the transection site. 14 weeks later, the spinal cord were removed and sectioned transversly with a microtome from T9 to T11, including the transection site, which could be visualized externally. The sections were stained for collagen with Masson＇ s trichrome and percentage of collagen infiltration in cross sections of the lesion epicenter was measured by immunohistochemistry. CSPGs（Chondroitin sulfate proteoglyeans） and GFAP immunoreactivity was detected by fluorescence staining under confocal microscope and the minimum GFAP negative gap length in lesion site was measured. Results ehABC application decreased collagen infiltration after SCI.The maximum distance of collagen infiltrate into transection site and the measurement of percentage of collagen infiltration in cross sections of the SCI site were significantly decreased in chABC group （ P 〈0.05 ）. chABC treatment also decreased the minimum GFAP negative gap length in lesion site （ P 〈0.05 ）, which indicates that more spinal cord tissue was spared in chABC group. The inhibitory extracellular matrix molecules（CSPGs） was found significantly decreased in the glial scar by chABC treatment （ P 〈0.05 ） . Conclusion chABC could decrease the infiltration of connective tissue after complete spinal cord transection, reduce the glial scar, and remove the inhibitor CSPGs, produce a proregenerative envioronment for injured axons.