牡荆素对脊髓损伤大鼠运动功能和炎症反应的影响

Effect of vitexin on motor function and inflammation in rats with spinal cord injury

  • 摘要: 目的:探究牡荆素(VT)对脊髓损伤(SCI)大鼠和脂多糖(LPS)诱导的BV2小胶质细胞的影响。方法:体内实验:将SD大鼠分为假手术组(sham组)、模型SCI组(SCI组)和VT低剂量组、VT中剂量组和VT高剂量组。采用Basso-Beattie-Bresnahan(BBB)评分评估大鼠的运动功能;实时荧光定量PCR(RT-qPCR)和酶联免疫吸附实验(ELISA)检测大鼠炎症因子基因和蛋白表达;苏木精—伊红(HE)染色观察脊髓组织结构。体外实验:将BV2小胶质细胞分为正常对照组(control组)、LPS组、VT低、中、高、剂量组和VT高剂量单独给药组,LPS诱导BV2小胶质细胞活化构建体外神经炎症模型;细胞计数试剂盒(CCK-8)法筛选VT安全浓度范围;RT-qPCR和蛋白质免疫印迹法(western blotting)检测细胞炎症基因和蛋白表达水平。结果:体内实验:与SCI组比较,VT中、高剂量组的BBB评分明显升高,损伤第7天,VT中剂量组评分显著高于VT高剂量组(均P<0.05);VT中剂量组TNF-α mRNA表达较SCI组降低,VT中、高剂量组IL-10 mRNA表达较SCI组显著升高(均P<0.05);VT低剂量组、VT中剂量组和VT高剂量组的TNF-α蛋白水平显著降低(均P<0.05),VT各剂量组的IL-10蛋白水平显著升高(均P<0.05);HE结果显示,sham组脊髓组织结构完整,神经元数量较多、排列较为规则整齐;SCI组脊髓组织炎症细胞浸润,出现较多空洞,神经元减少萎缩且排列不整齐;与SCI组比较,VT治疗组损伤更小,炎症浸润减轻较为明显。体外实验:与LPS组相比,VT各剂量组的TNF-α m RNA表达显著降低(均P<0.05),且成剂量依赖性降低;VT各剂量组TNF-α蛋白表达量降低(均P<0.001)。结论:VT通过抑制大鼠炎症反应,减轻脊髓组织病理学损伤,改善损伤后脊髓局部微环境,从而保护受损脊髓神经元,达到促进运动功能恢复的作用。

     

    Abstract: Objective: To investigate the effect of vitexin(VT) on spinal cord injury(SCI) rats and lipopolysaccharide(LPS)-induced BV2 microglia. Methods: In vivo experiments: SD rats were divided into sham-operated group(sham group), model SCI group(model group) and VT low-dose, VT medium-dose and VT high-dose groups. Basso-Beattie-Bresnahan(BBB) score was used to evaluate the motor function of rats; reverse transcription-quantitative PCR(RT-qPCR) and enzyme-linked immunoassay(ELISA) were used to detect the gene and protein expression of inflammatory factors in rats; hematoxylin-eosin(HE) staining was used to observe the spinal cord tissue structure. In vitro experiments: BV2 microglia were divided into normal control group(control group), LPS group, VT low-dose, medium-dose and high-dose groups and VT high-dose alone administration group; LPS-induced BV2 microglia activation was used to construct in vitro neuroinflammation model; cell counting kit-8(CCK-8) method was used to screen the range of safe concentration of VT; RT-qPCR and western blotting were used to detect the levels of cellular inflammatory gene and protein expression. Results: In vivo experiments: compared with the SCI group, the BBB scores of the VT medium-and high-dose groups were significantly higher, and the score of the VT medium-dose group was significantly higher than that of the high-dose group on the 7th day of the injury(both P<0.05); the expression of TNF-α mRNA in the VT medium-dose group was lower compared with that of the SCI group, and the expression of IL-10 mRNA in the VT medium-and highdose groups was significantly higher compared with that in the SCI group(both P<0.05); the protein levels of TNF-α in the VT low-dose group, VT medium-dose group and VT high-dose group were significantly decreased(all P<0.05), and the protein levels of IL-10 in the VT dose groups were significantly increased(all P<0.05);HE results showed that the spinal cord in the sham group was structurally intact, with more neurons and a more regular arrangement; spinal cord tissue in the SCI group was infiltrated with inflammatory cells, showed more cavities, and neurons were reduced and atrophied with irregular arrangement; compared with the SCI group, the damage in the VT treatment group was smaller, and the reduction of inflammatory infiltration was more obvious.In vitro experiments: compared with the LPS group, TNF-α mRNA expression was significantly reduced in each dose group of VT(all P<0.05), and reduced in a dose-dependent manner; TNF-α protein expression was reduced in each group of VT(all P<0.001). Conclusion: VT inhibits the inflammation of rats, reduces the histopathological damage of the spinal cord, and improves the local microenvironment of the spinal cord after injury, thereby protecting the damaged spinal cord neurons, and promoting the recovery of motor function.

     

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