红景天苷通过NF-κB途径调节小胶质细胞极化并减轻大鼠脊髓损伤后的神经炎症的机制

Salidroside attenuates neuroinflammation and improvesfunctional recovery after spinal cord injury via microgliapolarization regulation and NF-κB pathway.

目的探讨红景天苷减轻大鼠脊髓损伤后神经炎症的作用及其机制是否与调节小胶质细胞极化有关。方法选择40只雄性SD大鼠按照随机数字表法分为5组,每组各8只。假手术组实施假手术,腹腔注射0.9%氯化钠溶液1 mL。模型组、红景天苷低、中、高剂量组造成脊髓损伤模型,模型组腹腔注射0.9%氯化钠溶液1 mL,红景天苷低、中、高剂量组分别腹腔注射10、20、40 mg·kg^(-1)·d^(-1),干预28 d。通过脊髓损伤行为学(BBB)评分和斜坡试验评估各组大鼠运动功能。实时荧光定量聚合酶链式反应(PCR)检测各组大鼠脊髓中B细胞淋巴瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、核转录因子κB(NF-κB)、诱导型一氧化氮合酶(iNOS)和环氧化酶-2(COX-2)的mRNA表达。蛋白质印迹检测其脊髓中磷酸化单磷酸腺苷激活的蛋白激酶(p-AMPK)、磷酸化帕霉素靶蛋白(p-mTOR)的蛋白表达情况。结果与假手术组大鼠相比,脊髓损伤模型组大鼠运动功能受损,脊髓中M2/M1极化比下降,Bax、NF-κB、iNOS和COX-2 mRNA水平显著升高,Bcl-2 mRNA水平显著下降,p-AMPK表达水平明显降低,p-mTOR的表达水平显著升高,差异均有统计学意义(P<0.05);红景天苷低、中、高剂量组可显著恢复大鼠运动功能,增加脊髓中M2/M1极化比,降低Bax、NF-κB、iNOS和COX-2 mRNA水平,增加Bcl-2、p-AMPK表达、减少p-mTOR的表达,差异均有统计学意义(P<0.05)。其中,以红景天苷高剂量组作用最为显著。结论红景天苷可显著恢复脊髓损伤大鼠运动功能并减轻神经炎症,其机制主要通过调节小胶质细胞极化和AMPK/mTOR信号通路实现,且其作用效果存在一定剂量依赖。

Objective To investigate the effect of salidroside on reducing neuroinflammation after spinal cord injury in rats and whether the mechanism is related to the regulation of microglia polarization.Methods Forty male SD rats were selected and divided into 5 groups according to the random number table method,with 8 rats in each group.The sham operation group was given a sham operation,and 1 mL of 0.9%sodium chloride solution was injected intraperitoneally.The model group,low,medium and high dose salidroside groups were established as a spinal cord injury model.The model group was intraperitoneally injected with 0.9%sodium chloride solution 1 mL,and the salidroside low,medium,and high dose groups were intraperitoneally injected with 10 and 20,40 mg·kg^(-1)·d^(-1),respectively,intervention for 28 days.The motor function of rats in each group was evaluated by spinal cord injury behavior(BBB)score and ramp test.The mRNA expressions of B-cell lymphoma-2(Bcl-2),Bcl-2 related X protein(Bax),nuclear factor kappa B(NF-κB),inducible nitric oxide synthase(iNOS)and cyclooxygenase-2(COX-2)in the spinal cord of rats in each group were detected by real-time quantitative PCR,and the protein expressions of phosphorylated adenosine monophosphate activated protein kinase(p-AMPK),phosphorylated pamycin target protein(p-mTOR)in the spinal cord of rats in each group were detected by Western blotting.Results Compared with the sham group,the motor function of the SCI model group was impaired,the M2/M1 polarization ratio in the spinal cord was decreased,the mRNA levels of Bax,NF-κB,iNOS and COX-2 were significantly increased,the mRNA levels of Bcl-2 were significantly decreased,the expression level of p-AMPK was significantly decreased,and the expression level of p-mTOR was significantly increased,the differences were statistically significant(P<0.05).The salidroside low,medium,and high dose groups could significantly promotes the functional recovery,increase the M2/M1 polarization ratio in the spinal cord,decrease the mRNA levels of Bax,NF-κB,iNOS and COX-2,increase the expression of Bcl-2 and p-AMPK,and decrease the expression of p-mTOR,,the differences were statistically significant(P<0.05).Conclusion Salidroside can significantly restore motor function and reduce neuroinflammation in rats with spinal cord injury.Its mechanism is mainly achieved by regulating the microglial polarization and AMPK/mTOR signaling pathway,and its effect is dose-dependent.