ANA-12通过靶向阻断BDNF/TrkB信号通路降低大鼠的脊髓炎症和缓解病理性疼痛

目的 探讨ANA-12靶向阻断脑源性神经营养因子（BDNF）/原肌球蛋白受体激酶B（TrkB）信号对炎症痛的抑制作用及机制。方法 将42只大鼠随机分为7组（6只/组）：BDNF处理下的对照组、ANA-12处理组、BDNF处理组以及BDNF和ANA-12联合处理组（BDNF+ANA-12）；炎症痛模型下的对照组、CFA处理组以及CFA和ANA-12联合处理组（CFA+ANA-12）。给药完毕后，对各组大鼠进行痛觉行为学检测，记录ANA-12处理对BDNF-急性痛和CFA-慢性炎症痛大鼠痛觉行为的影响；采用免疫印迹法检测各组大鼠脊髓组织TrkB信号、小胶质细胞标记蛋白Iba1和促炎细胞因子TNF-α以及炎症因子IL-1β、Caspase-1、NLRP3的表达水平。结果 与对照组相比，BDNF增加自发缩足次数（P<0.05）；与BDNF组相比，ANA-12降低自发缩足次数（P<0.05）。与对照组相比，CFA增加同侧机械刺激敏感性（P<0.05）；与CFA组相比，ANA-12增加同侧缩足阈值（P<0.05）。与对照组相比，BDNF和CFA增加磷酸化TrkB（Y705）水平（P<0.05）；与BDNF或CFA组相比，ANA-12降低TrkB（Y705）磷酸化水平（P<0.05）。与对照组相比，BDNF和CFA上调Iba1、TNF-α以及炎症因子表达（P<0.05）；与BDNF或CFA组相比，ANA-12降低Iba1、TNF-α以及炎症因子表达水平（P<0.05）。结论 ANA-12靶向阻断BDNF/TrkB信号可降低脊髓炎症并缓解急性痛和慢性痛。

ANA-12 inhibits spinal inflammation and alleviates acute and chronic pain in rats by targeted blocking of BDNF/TrkB signaling

Objective To investigate the inhibitory effect of ANA-12 that blocks brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling on inflammatory pain in rats and explore the underlying mechanism. Methods Forty-two adult SD rats were randomized into BDNF-induced acute pain group (n=24) and CFA-induced chronic pain group. The former group were randomly divided into 4 subgroups, including a control group, ANA-12 treatment group, BDNF treatment group, and BDNF+ANA-12 treatment group; the latter group were subgrouped into control group, CFA treatment group (CFA) and CFA + ANA-12 treatment group. The effects of ANA-12 treatment on pain behaviors of the rats with BDNF-induced acute pain and CFA-induced chronic inflammatory pain were observed. Western blotting was used to examine TrkB signaling and expressions of microglia marker protein Iba1 and TNF-α in the spinal cord of the rats. Results BDNF injection into the subarachnoid space significantly increased the number of spontaneous paw withdrawal of the rats (P<0.05), which was obviously reduced by ANA-12 treatment (P<0.05). The rats with intraplantar injection of CFA, showed significantly increased ipsilateral mechanical stimulation sensitivity (P<0.05), and ANA-12 treatment obviously increased the ipsilateral foot withdrawal threshold (P<0.05). Treatment with either BDNF or CFA significantly increased the phosphorylation level of TrkB (Y705) in the spinal cord of the rats (P<0.05), which was significantly lowered by ANA-12 treatment (P<0.05). Treatment with BDNF and CFA both significantly up-regulated the expressions of Iba1 and TNF-α in the spinal cord (P<0.05), but ANA-12 significantly reduced their expression levels (P<0.05). Conclusion ANA-12 can reduce spinal cord inflammation and relieve acute and chronic pain in rats by targeted blocking of BDNF/TrkB signaling.