脊髓损伤小鼠中甘草苷通过抑制MAPK通路抑制炎症和神经元凋亡

Liquiritin suppresses inflammation and apoptosis in a mouse model of spinal cord injury via inhibiting the MAPK signaling pathway

目的 研究甘草苷对脊髓损伤小鼠中炎症和神经元凋亡的影响。方法 将48只C57BL/6小鼠随机均分为假手术组(Sham组)、脊髓损伤模型组(SCI组)、低剂量甘草苷组(LQ-L组)、高剂量甘草苷组(LQ-H组),每组12只。采用脊髓打击器撞击脊髓建立脊髓损伤模型,LQ-L组和LQ-H组分别予以低剂量(30 mg/kg)和高剂量(60 mg/kg)甘草苷灌胃。采用后肢运动功能评分(BMS)评估小鼠运动功能。取脊髓组织,HE染色观察病变面积,比色法检测髓过氧化物酶活性,TUNEL检测细胞凋亡,Nissl染色观察神经元丢失,免疫荧光双染检测caspase 3阳性神经元数量,Western blotting检测MAPK通路蛋白表达。结果 脊髓损伤明显降低了小鼠运动功能,促进了脊髓炎症、病变面积、神经元凋亡及p-ERK、p-p38 MAPK、p-JNK蛋白表达(P <0.05)。LQ-H组术后第14、21天,脊髓损伤小鼠运动功能明显提高(P <0.05)。LQ-L组和LQ-H组脊髓炎症、病变面积、神经元凋亡及p-ERK、p-p38 MAPK、p-JNK蛋白表达均明显抑制(P <0.05)。LQ-H组与LQ-L组相比,在抑制炎症、病变面积、神经元凋亡、p-ERK和p-p38 MAPK蛋白表达方面效果更明显(P <0.05)。结论 甘草苷可能通过抑制MAPK通路抑制炎症和神经元凋亡,减轻小鼠脊髓损伤。

Objective To investigate the effects of liquiritin on inflammation and neuron apoptosis in mice with spinal cord injury.Methods In this study,48 C57BL/6 mice were randomly classified into the sham operation group(Sham group),spinal cord injury model group(SCI group),low-dose liquiritin group(LQ-L group),and high-dose liquiritin group(LQ-H group),with 12 mice per group. The SCI model was established by hitting the spinal cord with a spinal cord beater. The mice in LQ-L and LQ-H groups were administered 30 and 60 mg/kg liquiritin,respectively. The Basso Mouse Scale(BMS) was used to evaluate the motor function of mice. Spinal cord tissues were extracted. The lesion area was observed using hematoxylin and eosin staining. The myeloperoxidase activity and apoptosis were detected using colorimetry and TUNEL assay,respectively. Further,neuron loss was observed using Nissl staining,and the caspase 3-positive neurons were detected using immunofluorescence staining. The expressions of the mitogen-activated protein kinase(MAPK) pathway proteins were detected using Western blotting. Results SCI reduced the motor function and promoted inflammation,lesion area,neuron apoptosis,and the expressions of p-ERK,p-p38 MAPK,and p-JNK proteins(P < 0.05). In the LQ-H group,the motor function improved on days 14 and 21 after surgery(P < 0.05). In the LQ-H and LQ-L groups,inflammation,lesion areas,neuronal apoptosis,and the expressions of p-ERK,p-p38 MAPK,and p-JNK proteins were inhibited(P < 0.05). The effects of inhibiting inflammation,lesion area,neuron apoptosis,and expressions of p-ERK and p-p38 MAPK proteins were more obvious in the LQ-H group than those in the LQ-L group(P < 0.05).Conclusion Liquiritin might suppress inflammation and apoptosis in SCI mice via inhibiting the MAPK signaling pathway.