CXCR4对大鼠背根神经节中交感芽生形成的干预作用

Effect of CXCR4 on sympathetic sprouting in dorsal root ganglion of rats

目的 研究CXCR4在大鼠脊神经结扎（spinal nerve ligation, SNL）后对背根神经节（dorsal root ganglion, DRG）交感芽生形成的干预作用。方法 将大鼠随机分为AMD3100（CXCR4特异抑制剂）实验组（n=16）、AMD3100对照组（n=8）、对照组（n=16）和空白对照组（n=16），对AMD3100实验组和对照组的大鼠行SNL术，术后7天内对AMD3100实验组大鼠每天给予AMD3100，术后3、5、7、10、14天（d3、d5、d7、d14）检测机械痛阈（mechanical withdrawal threshold, MWT），分别用实时PCR和Western blot检测神经生长因子（nerve growth factor, NGF）的RNA和蛋白质水平，d7和d14行免疫荧光检测DRG中交感芽生。结果 与对照组相比，AMD3100实验组大鼠在d5、d7和d14的MWT均显著缓解，抑制CXCR4后，AMD3100实验组大鼠DRG中交感芽生在d7较对照组显著减少，但在d14减少不明显，且NGF的RNA和蛋白质水平均较对照组显著降低。结论 抑制CXCR4能改善大鼠SNL术后d5～d14的疼痛行为，并能减少d7的蓝状结构数量。

Objective To explore the role of CXCR4 in sympathetic sprouting in dorsal root ganglion （DRG） after spinal nerve ligation （SNL） in rats. Methods Rats were randomly divided into AMD3100 treatment group （n=16）, control group （n=16）, AMD3100 control group （n=8） and naive group （n=16）. SNL was performed in the rats in AMD3100 treatment group and control group. AMD3100, the inhibitor of CXCR4, was injected intrathecally into the rats of AMD3100 treatment group 1-7 days after SNL. Mechanical withdrawal threshold （MWT） was detected at d3, d5, d7, d10 and d14. Real-time PCR and Western blot were applied to detect the levels of RNA and protein of nerve growth factor （NGF）, respectively. Sympathetic sprouting in DRG was detected by immunofluorescence at d7 and d14. Results The MWT of rats in AMD3100 treatment group was significantly improved compared with which in control group from d5 to d14. After the inhibition of CXCR4, sympathetic sprouting in DRG was dramatically decreased compared with which in control group at d7, but not at d14. In addition, The RNA and protein levels of rats in AMD3100 treatment group was significantly decreased compared with which of control group. Conclusions The inhibition of CXCR4 could not only improved pain behavior from d5 to d14, but also decreased basket-like structures at d7 after SNL.