穴位电针刺激对局灶性脑缺血再灌注大鼠基质细胞衍生因子/CXC类趋化因子受体4信号轴的影响

Expression of the stromal cell derived factor-1α and chemokine CXC motif receptor 4 axis is promoted by electroacupuncture

目的 探讨穴位电针刺激对局灶性脑缺血再灌注大鼠基质细胞衍生因子（SDF-1α）/CXC类趋化因子受体4（CXCR4）信号轴的影响.方法 选取SD大鼠98只,按照随机数字表法将其分为对照组（8只）、模型组（50只）和电针组（40只）,根据造模后观察时间点的不同,将模型组和电针组大鼠细分为第1、3、7、14、21天5个亚组.采用线栓法对模型组和电针组大鼠进行造模,制备大鼠局灶性脑缺血再灌注模型,在电针组大鼠双侧合谷穴采用电针刺激,对照组和模型组不作特殊处理.采用免疫组化法检测模型组与电针组大鼠CXCR4阳性细胞的数目,第3、7、14天时采用逆转录聚合酶反应法（RT-PCR）检测模型组和电针组大鼠SDF-1α mRNA及CXCR4 mRNA的表达量.结果 造模后,模型组大鼠缺血区大脑皮质SDF-1α mRNA的表达水平随再灌注时间延长呈单峰样增加,造模后3d（0.971 ±0.058）明显升高,7 d（1.057 ±0.054）达峰值,随后逐渐下降（P＜0.05）.造模后3d、7d、14 d,电针组大鼠SDF-1α mRNA表达亦呈单峰样变化,造模后7d达峰值（P＜0.05）,且电针组大鼠SDF-1 αmRNA水平较模型组同时间点高（P＜0.05）.模型组与电针组造模后7d、14 d的CXCR4 mRNA相对值均高于组内造模后3 d（P ＜0.05）,造模后14d时的CXCR4 mRNA相对值亦高于组内造模后7 d（P ＜0.05）,与模型组同时间点比较,电针组大鼠CXCR4 mRNA相对值均较高,差异有统计学意义（P＜0.05）.模型组大鼠CXCR4阳性细胞于造模后1 d[（5.60 ±1.18）个/HP]开始增加,7d[（18.93±1.38）个/HP]达峰值,14 d[（8.20±1.08）个/HP]开始回落,21d[（5.80±1.01）个/HP]的表达量仍然较高（P＜0.05）.电针组大鼠CXCR4阳性细胞计数的变化趋势与模型组相似,但电针组的增加趋势更加明显（P＜0.05）.结论 穴位电针刺激可激活局灶性脑缺血再灌注大鼠缺血区大脑皮质的SDF-1α/CXCR4信号轴,促进血管新生.

Objective To investigate the stromal cell derived factor 1 α （SDF-1 α） and chemokine CXC motif receptor 4 （CXCR4） axis using acupoint electroacupuncture （EA） on the brains of rats after focal cerebral ischemia and reperfusion.Methods Ninety-eight Sprague-Dawley （SD） rats were randomly divided into a control group （8 rats）,a model group （50 rats）,and an EA group （40 rats）.The animal model of focal brain ischemia-reperfusion was made with all the rats in the model group and EA group by using the filament occlusion technique.The model and EA groups were subdivided into 5 subgroups according to the sampling time points on the 1 st,3rd,7th,14th or 21st day after ischemia-reperfusion.The EA was administered bilaterally to the rat analog of the Hegu point （LI 4） in the EA group.The model and control groups received no special treatment.Immunohistochemical methods were employed to detect CXCR4-positive cells in the model and EA groups.The expressions of SDF-1α and CXCR4 mRNA were detected with RT-PCR methods in the 3rd,7th and 14th day subgroups.Results With the prolongation of reperfusion,SDF-1α mRNA expression in the model group had a single peak-like increase in the ischemic area of the cerebral cortex.It had increased significantly by the 3rd day,reached its peak value at the 7th day and then decreased gradually.SDF-1α mRNA expression in the EA group behaved similarly,but SDF-1 mRNA expression was significantly higher in the EA group than in the other two.In the model and EA groups CXCR4 mRNA relative values were higher at the 7th and 14th day than at day 3,and the expression at day 14 was significantly greater than at day 7.CXCR4 mRNA values in the EA group were significantly higher than in the model group at each time point.The expression of CXCR4-positive cells began to increase on the 1 st day in the model group,reached its peak value at the 7th day,then decreased by day 14,but it was still strongly expressed highly at the 21st day.Compared with the model group,the expression in the EA group showed the same pattern,but the number of CXCR4-positive cells in EA group was significantly higher.Conclusion Point EA can activate the SDF-1α and CXCR4 axis to promote angiogenesis after focal cerebral ischemia and reperfusion,at least in rats.