Objective To explore the effect of shionone(SHI)on motor function in the mouse model of spinal cord injury(SCI)and probe into the underlying molecular mechanism.Methods C57BL/6 mice were treated to induce the SCI model and then assigned into a model group(SCI group),a SCI+SHI group,and a sham surgery(control)group.The Basso mouse scale(BMS)score was determined to evaluate the recovery of motor function in SCI mice.Hematoxylin-eosin(HE)staining,Nissl staining,and immunofluorescence staining were employed to examine the fibrosis,morphological changes of neurons,and neuron apoptosis in the spinal cord tissue of SCI mice,respectively.The mouse hippocampal neuronal cell line HT22 was cultured in vitro and then classified into tumor necrosis factor α(TNF-α)induction and SHI groups.Western blotting was employed to determine the expression of apoptosis-associated proteins.Network pharmacology,gene ontology annotation,and Kyoto Encyclopedia of Genes and Genomes pathway enrichment were employed to predict the possible molecular targets and signaling pathways of SHI in promoting functional recovery from SCI.Furthermore,the prediction results were verified by in vitro and in vivo experiments.Results Compared with the SCI group,the SCI+SHI group showed increased BMS score on days 21,28,35,and 42(P=0.003,P=0.004,P=0.023,and P=0.007,respectively),reduced area of spinal cord fibrosis(P=0.021),increased neurons survived(P=0.001),and down-regulated expression of cleaved cysteine aspastic acid-specific protease 3(cleaved Caspase-3)(P=0.017).Compared with the TNF-α group,the SHI group presented down-regulated expression levels of cleaved Caspase-3 and Bax(P=0.010,P=0.001)and up-regulated expression level of Bcl-2(P=0.001).The results of bioinformatics analysis showed that SHI might improve the motor function of SCI mice via the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)signaling pathway.The results of in vivo and in vitro experiments showed that SHI inhibited the phosphorylation of PI3K and Akt in SCI mice or HT22 cells exposed to TNF-α(all P<0.05).The number of apoptotic HT22 cells after treatment with insulin-like growth factor 1 was higher than that in the SHI group(P=0.003).Conclusion SHI may inhibit neuron apoptosis via the PI3K/Akt signaling pathway,thereby promoting the recovery of motor function in SCI mice.
目的 探讨紫菀酮(SHI)对脊髓损伤(SCI)小鼠运动功能的影响及可能的分子机制。方法 采用C57BL/6小鼠构建SCI模型,分为模型组(SCI组)和SHI药物治疗组(SCI+SHI组),假手术小鼠为对照组。采用Basso小鼠量表(BMS)评分评估SCI小鼠运动功能恢复情况,采用HE染色和Nissl染色观察SCI小鼠脊髓组织纤维化和神经元的形态学变化,采用免疫荧光染色分析脊髓组织中神经元凋亡情况。体外培养小鼠海马神经元HT22细胞,分为肿瘤坏死因子α(TNF-α)诱导组和SHI药物治疗组,采用Western blot检测各组细胞凋亡相关蛋白的表达。利用网络药理学、基因本体和京都基因与基因组百科全书富集分析预测SHI促进SCI功能恢复的可能分子靶点和信号通路,并通过体内外实验对其分子机制进行验证。结果 与SCI组比较,SCI+SHI组小鼠BMS评分在第21、28、35、42天显著升高(P=0.003、P=0.004、P=0.023、P=0.007),脊髓组织纤维化面积显著降低(P=0.021),神经元存活数量显著增加(P=0.001),活化的半胱氨酸天冬氨酸蛋白酶3(cleaved-Caspase3)表达显著降低(P=0.017)。与TNF-α组比较,SHI组cleaved-Caspase3、Bax蛋白表达水平显著降低(P=0.010、P=0.001),而Bcl-2蛋白表达水平显著升高(P=0.001)。生物信息学分析结果显示SHI改善SCI小鼠运动功能可能与磷脂酰肌醇3-激酶(PI3K)/蛋白激酶 B(Akt)信号通路相关。体内和体外实验检测结果显示,SHI可抑制SCI小鼠或TNF-α诱导的HT22细胞中PI3K和Akt的磷酸化水平(P均<0.05),而胰岛素样生长因子-1干预后HT22细胞凋亡数量显著高于SHI组(P=0.003)。结论 SHI可能通过PI3K/Akt信号通路抑制神经元凋亡,从而促进SCI小鼠运动功能恢复。.
Keywords: apoptosis; neuron; phosphatidylinositol 3-kinase/protein kinase B; shionone; spinal cord injury.