基于GFAP/STAT3通路探讨夹脊电针对脊髓损伤修复的作用

Effect of Jiaji electroacupuncture on spinal cord injury repair based on the GFAP/STAT3 pathway

目的探讨夹脊电针(EA)改善脊髓损伤(SCI)大鼠神经元凋亡的相关机制。方法将SD大鼠随机分为sham组、SCI组、EA组和EA+激动剂组,每组10只。Allen’s改良式重物坠落法制备脊髓损伤动物模型。EA组在大鼠背部SCI处上下两端T7~9的椎体旁夹脊穴进行电针治疗。采用Basso-Beattie-Bresnahan(BBB)评分和斜坡实验评价大鼠的运动能力,TUNEL染色检测脊髓神经元凋亡的变化情况,免疫荧光检测大鼠脊髓组织中胶质纤维酸性蛋白(GFAP)表达的变化,Western blotting法检测脊髓组织中GFAP、磷酸化信号转导和转录激活因子3(p-STAT3)、STAT3和cleaved caspase-3蛋白的相对表达量。结果EA组的BBB得分高于SCI组(P<0.01)。斜坡实验中EA组的角度小于sham组(P<0.001)。EA组较SCI组角度略大(P<0.01)。与sham组比较,SCI组GFAP阳性表达,p-STAT3、cleaved caspase-3蛋白表达及炎性细胞因子含量显著增加(P<0.05),神经元凋亡数量增加(P<0.01)。EA组则出现相反趋势。然而,给予STAT3激活剂干预后,EA对SCI治疗作用被逆转(P<0.05)。结论EA可减少SCI大鼠脊髓组织中的神经元凋亡,改善SCI大鼠运动和平衡功能,其机制可能与抑制GFAP/STAT3通路有关。

Objective To investigate the mechanism underlying the Jiaji electroacupuncture(EA)-induced improvement in neuronal apoptosis among rats with spinal cord injury(SCI).Methods Sprague-Dawley rats were randomly divided into sham,SCI,EA,and EA+colivelin groups(n=10 each).Allen’s modified heavy-fall method was used to prepare the animal model of SCI.The clamped-spine EA group was treated with EA at the paraspinal clamped spine points at the vertebral bodies of T7-9 at the upper and lower ends of the spinal cord injury on the backs of the rats.The Basso-Beattie-Bresnahan score and slope test were used to evaluate the rats’locomotor abilities;TUNEL staining was used to detect changes in neuronal apoptosis in the spinal cord;immunofluorescence was used to detect changes in glial fibrillary acidic protein(GFAP)expression in the rats’spinal cord tissues;and Western blotting was used to detect the relative expressions of GFAP,phospho-signal transducer and activator of transcription 3(p-STAT3),STAT3,and cleaved caspase-3 protein expression in spinal cord tissues.Results The mean Basso-Beattie-Bresnahan score was higher in the EA compared with SCI group(P<0.01).The mean angle on the slant plate test was smaller in the EA compared with sham group(P<0.001).The mean angle was slightly larger in the EA compared with SCI group(P<0.01).GFAP-positive,p-STAT3,cleaved caspase-3 protein,and inflammatory cytokine expressions were significantly increased(P<0.05)and the number of neuronal apoptotic cells was increased(P<0.01)in the SCI compared with sham group.However,the opposite trend was observed in the EA group.In addition,the therapeutic effect of spinal EA on spinal cord injury was reversed after colivelin administration(P<0.05).Conclusion EA reduces neuronal apoptosis and improves motor and balance functions in the spinal cord tissues of rats with SCI,possibly via GFAP/STAT3 pathway inhibition.