嗅鞘细胞移植脊髓损伤大鼠NG2的表达

Effects of olfactory ensheathing cells transplantation on NG2 expression in spinal cord injury rats

背景:对于脊髓损伤,目前临床尚无有效的治疗对策,近年来嗅鞘细胞移植治疗脊髓损伤修复取得了一定的进展。NG2是主要的硫酸软骨素蛋白多糖分子,对轴突有抑制作用。目的:观察嗅鞘细胞移植对脊髓损伤大鼠NG2表达的影响,进一步分析嗅鞘细胞移植在修复脊髓损伤中的作用途径。方法:将112只大鼠随机分为4组,空白组、模型组、嗅鞘细胞移植组及DF12组各28只。空白组仅切开T10全椎板及T9,T11部分椎板,对脊髓未作其他处理;其他3组应用脊髓横切法制作脊髓损伤动物模型。嗅鞘细胞移植组进行嗅鞘细胞移植,每侧断端植入20000 cells;DF12组于相同部位注射DF12培养液。在大鼠脊髓损伤后1,3,7,14,28,42和56d时,取材按照SP试剂盒的操作步骤检测NG2的表达。结果与结论:空白组NG2呈低表达,在模型组、DF12组脊髓损伤24h后损伤部位的NG2的表达开始升高,7d时达到顶点,4周时NG2表达明显降低,6,8周时仅在局部有所表达。嗅鞘细胞移植组脊髓损伤1d时NG2表达开始增加,主要在损伤部位,在各时间点与模型组、DF12组相比NG2表达水平明显降低,但高于空白组NG2各时间点的表达。提示嗅鞘细胞移植后NG2的表达水平降低,嗅鞘细胞具有抑制NG2表达的作用,可消除或减轻细胞外基质中对轴突有抑制作用的化学屏障,这可能是其治疗脊髓损伤促进轴突再生的机制之一。

BACKGROUND：There is no effective therapeutic strategy for spinal cord injury in clinic.Olfactory ensheathing cells（OECs） transplantation for spinal cord injury has obtained great progress.NG2,an important chondroitin sulfate proteoglycan molecule,suppresses axon growth.OBJECTIVE：To explore effects of OECs transplantation on expression of NG2 in spinal cord injury rats,and to analyze action pathway of OECs transplantation in repair of spinal cord injury.METHODS：A total of 112 rats were equally and randomly divided into four groups：blank group,model group,OECs group and DF12 group.In the blank group,rat spinal cord was completely transected at T10,and partially transected at T9 and T11.No other treatment was performed.Animal models of spinal cord injury were established using spinal cord transsection in other three groups.In the OECs group,OECs transplantation was performed.Each transplanted rat received a total of 20 000 cells.In the DF12 group,DF12 culture medium was injected at the same area.At 1,3,7,14,28,42 and 56 days following spinal cord injury,NG2 expression was evaluated according to SP kit instructions.RESULTS AND CONCLUSION：In the blank group,NG2 appeared low expression.In the model group and DF12 group,NG2 expression increased at 24 hours.A highest expression of NG2 was present at 7 days.NG2 expression decreased obviously at 4 weeks.It only appeared local expression at 6 and 8 weeks.In the OECs group,moderately NG2 expression was presented on injury region at 1 day;the expression level was lower in the model group and DF12 group at identical time points,but higher than in the blank group.These indicate that NG2 expression was in a lower lever after OECs transplantation;it was inhibited by OECs transplantation.OECs transplantation would eliminate the chemical barrier of NG2,so that the injured nerve could regenerate.It may be one of the mechanisms of OECs transplantation for treating injured spinal cord.