排斥导向分子B对大鼠脊髓损伤后功能恢复的影响

Effects of repulsive guidance molecule B on functional recovery after spinal cord injury in rats

目的：探讨排斥导向分子（repulsive guidance molecule，RGM）B在大鼠脊髓损伤后的表达规律及其与脊髓功能恢复的相关性。方法：成年雄性SD大鼠65只，随机分成3组，A组：不应用硫酸软骨素酶ABC（chondroitinase ABC，ChABC）降解25只；B组：应用硫酸软骨素酶降解20只；C组：假手术组只暴露脊髓20只。A、B、C3组分别在术后相同时间位点观察记录动物肢体运动情况并处死动物进行标本检测。采用BBB（Basso—Beattie—Blesnahan）评分法评价大鼠后肢的感觉、运动功能；HE染色计算损伤区总面积；Real—time PCR检测RGMBmRNA的表达；应用免疫荧光检测胶质纤维酸性蛋白（glial fibrillary acidic protein，GFAP）及神经丝蛋白-200（neurofilament-200，NF-200）双标表达情况。结果：伤后2-4周同一时间段B组BBB评分显著高于A组（P〈0．05）；伤后2周HE染色结果表明，2组损伤区均有空洞形成，B组损伤区面积显著小于A组（P〈0．05）；伤后2到4周GFAP／NF-200双重免疫荧光染色示B组GFAP表达逐渐下调，A组荧光强度值显著高于B组（P〈0．05）；NF-200免疫组化染色阳性纤维穿过损伤区，B组荧光强度值显著高于A组（P〈0．05）；RGMB mRNA表达量B组显著较A组下降（P〈0．05）。结论：微环境中的RGMB浓度在大鼠脊髓损伤后与其后期脊髓功能恢复呈负相关，RGMB抑制剂可能对临床治疗脊髓损伤有一定作用。

Objective：To explore the expression rule of repulsive guidance molecule B （RGMB） after spinal injury in rats and its correlation with the spinal cord functional recovery. Methods ： Totally 65 adult male SD rats were divided into A, B, C groups randomly. Chondroitin sulfate（chondroitinase ABC, ChABC） enzyme was not applied to do degradation in group A （n=25）. ChABC was used to do degradation in group B（n=20）. Only spinal cord was exposed in group C（n=20）. Body movements were recorded in three groups at the same postoperative time points. Rats were executed to do specimen detection. Basso-Beattie-Bresnahan（BBB） score was used to evaluate the feeling and movement of rat＇s hindlegs. HE staining was employed to calculate the total damage. Real-time PCR was used to detecte RGMB mRNA expression.Inmmnofluorescence staining was used to observe the double standard expression of glial fibrillary acidic protein （GFAP） and neurofilament-200 （NF-200）. Results：Within the same period at 2-4 weeks after the injury, BBB score was obviously higher in group B than in group A （P〈0.05）. Two weeks after the injury, HE staining demonstrated hollow formation in A and B groups; damaged area was significantly smaller in group B than in group A（P〈0.05）. At 2-4 weeks after the injury, GFAP/NF-200 double immunofluorescence staining demonstrated that GFAP expression was gradually lower in group B and immunofluorescence intensity value was significantly higher in group A than in group B （P〈0.05） ;NF-200 positive staining fibers passed through the damaged area and immunofluorescence intensity value was significantly higher in group B than in group A（P〈0.05）.RGMB mRNA expression was decreased in group B than in group A （P〈0.05）. Conclusions：After spinal cord injury in rats, RGMB concentration in the microenvironment is negatively correlated with the spinal cord functional recovery. RGMB inhibitors may be helpful for clinical treatment of spinal cord injury.