椎间盘脱出模型大鼠脊髓血管生成因子mRNA的表达变化及电针对其影响

Changes of expression of angiogenic factor mRNA in the spinal cord of rat models of protruded intervertebral disc and the effects of electroacupuncture

目的探讨椎间盘脱出症中与血管生成相关因子的变化及其电针作用,分析电针参与脊髓微血管生成的机理。方法采用自制硅胶片在T13段脊髓的左腹侧位压迫建立椎间盘脱出模型,将大鼠随机分为三组,即电针治疗组(n=6)、模型组(n=6)、假手术组(n=6),电针组每日电针治疗一次,模型组与假手术组不做任何治疗。术后7 d后取压迫部位脊髓组织,RT-PCR法检测Ang-1、Tie-1、Ang-2、Tie-2、VEGF、Flt-1、caspase-3、Tsp-1的mRNA表达量,组织切片法观察脊髓损伤情况。结果电针组大鼠后肢运动机能显著改善;脊髓组结构相对完整,灰质、白质界限清晰;荧光定量PCR结果显示模型组与假手术组相比Ang-1、Ang-2、Tie-1、Tie-2、caspase-3、Tsp-1表达极显著升高(P<0.01),VEGF、Flt-1差异无显著性(P>0.05);模型组与电针组相比Ang-2、Tie-1、Tie-2、caspase-3、Tsp-1极显著升高(P<0.01),Ang-1、VEGF、Flt-1差异无显著性(P>0.05);电针组与假手术组各指标差异均无显著性(P>0.05);结论脊髓压迫损伤后血管生成相关因子mRNA表达异常,电针能够下调Ang-2、Tie-2、Tsp-1和caspase-3的表达,使血管生成促进因子和抑制因子水平趋于正常,从而为受损脊髓组织的修复提供有利条件。

Objective The purpose of this study was to determine the changes of expression of angiogenic factor mRNA in the spinal cord of rats with protruded intervertebral disc and the effects of electroacupuncture,and to analyze the role of electroacupuncture in the spinal microvascular angiogenesis. Method Eighteen healthy male Sprague-Dawley rats were divided randomly into 3 groups: the electroacupuncture group,model group and sham-operated group. The protruded intervertebral disc models were generated by the left lateral and ventral spinal cord compression at T13 using a self-made silicon sheet. Only the rats in the first group were treated by electroacupuncture once a day for consecutive 7 days. Spinal cord tissue samples were taken from the compression site at 7 days after operation. The mRNA levels of Ang-1,Tie-1,Ang-2,Tie-2,VEGF,Flt-1,caspase-3 and Tsp-1 were determined by RT-PCR,and the pathological changes of the spinal cord was examined using HE staining. Results The rats in the electroacupuncture treated group showed significantly improved hind leg function,a relatively complete spinal cord structure,and a clear boundary between grey and white matters.The expression levels of Ang-1,Ang-2,Tie-1,Tie-2,capase-3 and Tsp-1 in the spinal cord tissues of the model group were significantly higher than those of sham-operated group( P < 0. 01),but the levels of VEGF and Flt-1 between those two groups showed no significant difference( P > 0. 05). The expression levels of Ang-2,Tie-1,Tie-2,caspase-3 and Tsp-1 of the electroacupuncture group were significantly lower than those in the model group( P < 0. 01),while the expression levels of Ang-1,VEGF and Flt-1 were not significantly different between the two groups( P > 0. 05). All the indexes between electroacupuncture and sham-operated groups showed no significant difference( P > 0. 05). Conclusions Our results demonstrate that mRNA expression of relevant angiogenic factors were abnormal after spinal cord compression,while electroacupuncture can down-regulate the expression of Ang-2,Tie-2,Tsp-1 and caspase-3,and modulate the promoting and inhibiting factors of angiogenesis to return towards normal,therefore,to create beneficial conditions for the repair of spinal cord injuries.