针刺对中型创伤性颅脑损伤后BDNF/TrkB信号通路的影响

Effect of acupuncture on BDNF/TrkB signaling pathway after moderate traumatic brain injury

目的探讨针刺对中型创伤性颅脑损伤(TBI)后脑源性神经营养因子(BDNF)表达和激活酪氨酸激酶受体B(TrkB)活性的影响。方法42只成年SD雄性大鼠按照随机数字表法分为TBI组(21只)和TBI+针刺组(21只)。2组大鼠均采用液压冲击法制备中型TBI模型,TBI组仅造模,TBI+针刺组在建立TBI模型后给予针刺治疗。造模后21 d获取2组大鼠脑组织匀浆液和切片;采用ELISA法检测BDNF的表达水平;采用免疫荧光染色在中型TBI后6、12 h检测TrkB蛋白的表达水平;采用Western blot在中型TBI后48、96和168 h检测TrkB蛋白表达水平,在12、48 h检测蛋白激酶B(Akt)和细胞外调节蛋白激酶1/2(ERK1/2)的表达情况。结果2组大鼠的BDNF蛋白表达水平在中型TBI后12 h时达到高峰,48 h逐渐下降。TBI+针刺组的BDNF蛋白水平在TBI后6、48、96、168 h均高于TBI组,差异具有统计学意义(P<0.05);在12 h的BDNF蛋白水平比较差异无统计学意义(P>0.05)。TBI+针刺组的p-TrkB蛋白水平在6、12、48、96、168 h均高于TBI组,p-Akt、p-Erk1/2蛋白在12、48 h均高于TBI组,差异均具有统计学意义(P<0.05)。结论针刺疗法可上调中型TBI后BDNF蛋白的表达水平,还可通过TrkB蛋白磷酸化进而活化TrkB蛋白,最终激活其下游的信号通路。

Objective To investigate the effect of acupuncture on brain derived neurotrophic factor(BDNF)expression and receptor tyrosine kinase B(TrkB)activity after moderate traumatic brain injury(TBI).Methods Forty-two adult SD male rats were randomly divided into TBI group(21 rats)and TBI+acupuncture group(21 rats)according to random number table method.The moderate TBI model was established by fluid percussion instrument in both groups.The TBI group was only modeled,and the TBI+acupuncture group was given acupuncture treatment after the TBI model was established.Tissue homogenates and sections were harvested 21 d after moderate TBI.The level of BDNF was examined by ELISA.Immunofluorescence staining was used to detect the expression level of TrkB protein at 6 and 12 h after moderate TBI,Western blot was used to detect the expression levels of TrkB protein at 48,96,and 168 h after moderate TBI,and the expression of protein kinase B(Akt)and extracellular regulated protein kinase 1/2(ERK1/2)at 12 and 48 h.Results The expression level of BDNF protein in two groups of rats reached its peak at 12 h after moderate TBI and gradually decreased at 48 h.The BDNF protein levels in the TBI+acupuncture group were higher than those in the TBI group at 6,48,96,168 h after TBI,with statistical significance(P<0.05),there was no statistically significant difference in BDNF protein levels at 12 h(P>0.05).The levels of p-TrkB protein in the TBI+acupuncture group were higher than those in the TBI group at 6,12,48,96,168 h,while p-Akt and p-Erk1/2 protein levels were higher than those in the TBI group at 12,48 h,with statistical significance(P<0.05).Conclusion Acupuncture therapy can upregulate the expression level of BDNF protein after moderate TBI,and activate TrkB protein by phosphorylation,ultimately activating its downstream signaling pathway.