微囊化兔坐骨神经组织细胞移植对脊髓损伤后大鼠GDNF表达的影响

目的探讨微囊化兔坐骨神经组织细胞移植对脊髓半横断损伤后大鼠胶质细胞源性神经营养因子（GDNF）的表达影响。方法成年SD大鼠80只随机分为4组,微囊组（n=25）、细胞组（n=25）、单损组（n=25）、正常组（n=5）。术前制备兔坐骨神经细胞混悬液以及将其微囊化,微囊组、细胞组和单损组大鼠在脊髓半横断伤后,立即在损伤处分别植入10μl微囊化坐骨神经组织细胞1、0μl坐骨神经组织细胞以及10μl生理盐水。于术后2 d7、d1、4 d、21 d2、8 d（每个时相取5只大鼠）取出损伤部位脊髓组织,正常组（每个时相取1只大鼠）则取相应节段脊髓。组织石蜡包埋后切片,行免疫组织化学染色观察GDNF的表达变化。结果 GDNF阳性染色主要见于神经元细胞及胶质细胞的胞浆内。大鼠脊髓损伤后上述细胞2 d后表达开始上升2,1 d达到最高。微囊组与单损组、细胞组比较差异有显著性（P〈0.05）。结论微囊化兔坐骨神经组织细胞移植于大鼠损伤脊髓后,可以抑制炎症反应,促进GDNF的表达,有利于大鼠运动功能恢复。

Effects of transplantation of microencapsulated rabbit sciatic nerve on expressions of GDNF after spinal cord injury in rats

Objective To explore the effects of transplantation of microencapsulated rabbit sciatic nerve cells on glial cell line-derived neurotrophic factor（GDNF） expressions after spinal cord injury（SCI） in rats.Methods Eighty Sprague Dawley rats were randomly divided into four groups： microcapsule group（n=25）,cell group（n=25）,injury control group（n=25） and normal group（n=5）.The rabbit sciatic nerve cells suspension was prepared from rabbits.SCI was conducted by hemisection injury of spinal cord.Different groups were respectively implanted with 10 μl microencapsulated cells suspension（microcapsule group）,10 μl sciatic nerve cells suspension（cell group） and 10 μl physiological saline（injury control group）.Spinal cord tissues were taken out（five rats per hour） 2 days,7 days,14 days,21 days and 28 days after operation respectively,while corresponding tissues were collected（one rat per hour） in normal group.All tissues were embedded in paraffin and sectioned.Meanwhile,immunohistochemical stain was applied for the detection of GDNF.Results The GDNF positive staining was mainly seen in the cytoplasm of neurons and gliocytes.The expressions of GDNF were increased two days after SCI and were reached the highest leve1 21 days after SCI.The expression levels of GDNF in microcapsulated group were remarkably different from those in injury control group and cell group（P〈0.05）.Conclusion It suggests that the transplantation of microencapsulated rabbit sciatic nerve cells could suppress inflammatory reaction and improve the expressions of GDNF,thus accordingly promote the recovery of motor function in rats.