温肾通督方促进小鼠脊髓损伤的修复

Wen-Shen-Tong-Du Decoction promoting spinal cord injury repair in mice

背景:前期研究证实,温肾通督方可通过抑制脾脏B细胞焦亡、促进微血管内皮细胞吞噬髓鞘碎片、影响小胶质细胞迁移和浸润、促进受损神经元恢复、降低脊髓损伤后神经元凋亡等促进脊髓损伤恢复,但其机制尚不明确。目的:探讨温肾通督方对脊髓损伤小鼠髓系细胞触发受体2(triggering receptor expressed on myeloid cells 2,TREM2)及PI3K/Akt信号通路的影响。方法:取36只C57BL/6小鼠,采用随机数字表法分为假手术组、模型组、温肾通督方组,每组12只。模型组与温肾通督方组采用改良Allen’s法制备小鼠T10脊髓损伤模型,造模后第1天,温肾通督方组灌胃给予温肾通督方,假手术组、模型组灌胃给予生理盐水,每天1次,连续给药28 d。给药期间,通过BMS评分和斜板实验评价各组小鼠运动功能;造模后第7,28天,采用苏木精-伊红染色观察各组小鼠脊髓组织病理变化,免疫荧光染色双标法检测脊髓组织离子化钙结合适配分子1(ionized calcium binding adaptor molecule 1,IBA1)、TREM2蛋白表达,Western blot检测脊髓组织TREM2、PI3K、p-PI3K、Akt、p-Akt、Bcl2、Bax、Caspase3蛋白表达。结果与结论:①BMS评分和斜板实验结果表明,脊髓损伤造模后小鼠后肢运动功能下降,而经过温肾通督方治疗后,脊髓损伤小鼠后肢运动功能明显提升。②苏木精-伊红染色结果显示,与模型组比较,温肾通督方小鼠脊髓组织病理结构明显改善,表现为背侧白质和神经元萎缩程度、细胞质空泡化降低及炎性细胞浸润减少等。③免疫荧光染色结果显示,造模后第7天,模型组IBA1、TREM2蛋白表达均低于假手术组(P<0.05),温肾通督方组IBA1、TREM2蛋白表达均高于模型组(P<0.05);造模后第28天,模型组TREM2蛋白表达低于假手术组(P<0.05),温肾通督方组小鼠脊髓组织中的TREM2蛋白表达高于模型组(P<0.05)。④Western blot检测结果表明,造模后第7天,与假手术组相比,模型组TREM2、Akt蛋白表达及Bcl2/Bax比值降低(P<0.05),p-Akt、Bax蛋白表达及p-Akt/Akt比值升高(P<0.05);与模型组相比,温肾通督方组TREM2、PI3K、p-PI3K、Akt、p-Akt、Bcl2蛋白表达及p-PI3K/PI3K、p-Akt/Ak、Bcl2/Bax比值升高(P<0.05),Bax、Caspase3蛋白表达降低(P<0.05)。造模后第28天,与假手术组相比,模型组TREM2、PI3K、p-PI3K、Akt、p-Akt、Bcl2蛋白表达及Bcl2/Bax比值降低(P<0.05),Bax蛋白表达升高(P<0.05);与模型组相比,温肾通督方组TREM2、PI3K、Akt、p-Akt、Bcl2蛋白表达及Bcl2/Bax比值升高(P<0.05),Bax蛋白表达降低(P<0.05)。⑤结果表明,温肾通督方可能通过上调小胶质细胞TREM2激活PI3K/Akt信号通路,抑制神经元凋亡发挥神经保护作用,进而促进脊髓损伤的修复。

BACKGROUND:Previous studies have confirmed that Wen-Shen-Tong-Du Decoction can promote the recovery of spinal cord injury by inhibiting pyroptosis of splenic B cells,promoting the phagocytosis of myelin debris by microvascular endothelial cells,affecting the migration and infiltration of microglia,promoting the recovery of damaged neurons,and decreasing neuronal apoptosis after spinal cord injury,but the mechanism of this is still not clear.OBJECTIVE:To investigate the effect of Wen-Shen-Tong-Du Decoction on the triggering receptor expressed on myeloid cells 2(TREM2)and PI3K/Akt signaling pathways in mice following spinal cord injury.METHODS:Thirty-six C57BL/6 mice were selected and randomly divided into a sham-operation group,a model group and a Wen-Shen-Tong-Du Decoction group,with 12 mice in each group.In the model and Wen-Shen-Tong-Du Decoction groups,mouse models of T10 spinal cord injury were prepared by the modified Allen’s method.On the 1st day after modeling,the Wen-Shen-Tong-Du Decoction group was given Wen-Shen-Tong-Du Decoction by gavage,and the sham-operation group and the model group were given saline by gavage once a day for 28 days.During the drug administration period,mouse motor function was evaluated by Basso Mouse Scale score and inclined plane test.On the 7th and 28th days after modeling,hematoxylin-eosin staining was used to observe the histopathological changes in the spinal cord tissue of the mice;immunofluorescence double staining was used to detect the protein expression of ionized calcium binding adaptor molecule 1(IBA1)and TREM2;and western blot assay was used to detect the expression of TREM2,PI3K,p-PI3K,Akt,p-Akt,Bcl2,Bax and Caspase3 in spinal cord tissue.RESULTS AND CONCLUSION:Basso Mouse Scale scores and inclined plane test results indicated that the motor function of the mouse hindlimbs was declined after spinal cord injury,and Wen-Shen-Tong-Du Decoction significantly improved motor function in mice with spinal cord injury.Hematoxylin-eosin staining results revealed that Wen-Shen-Tong-Du Decoction significantly ameliorated the pathological structure of spinal cord tissue compared with the model group,manifesting as reduced degrees of dorsal white matter and neuronal atrophy,decreased cytoplasmic vacuolization,and reduced inflammatory cell infiltration.Immunofluorescence double staining results showed that on the 7th day after modeling,the protein expression of IBA1 and TREM2 in the model group was lower than that in the sham-operation group(P<0.05),and the protein expression of IBA1 and TREM2 in the Wen-Shen-Tong-Du Decoction group was higher than that in the model group(P<0.05);on the 28th day after modeling,the protein expression of TREM2 in the model group was lower than that in the shamoperation group(P<0.05),and the protein expression of TREM2 in the spinal cord tissue of the mice in the Wen-Shen-Tong-Du Decoction group was higher than that in the model group(P<0.05).Western blot results analysis demonstrated that on the 7th day after modeling,compared with the sham-operation group,the model group exhibited a significant reduction in TREM2,PI3K,and Bcl2/Bax(P<0.05),as well as a significant increase in p-Akt,Bax and p-Akt/Aktp-PI3K(P<0.05);compared with the model group,the Wen-Shen-Tong-Du Decoction group showed a significant increase in TREM2,PI3K,p-PI3K,Akt,p-Akt,Bcl2,p-PI3K/PI3K,p-Akt/Ak,and Bcl2/Bax(P<0.05),as well as a significant decrease in Bax and Caspase3 protein expression(P<0.05).On the 28th day after modeling,compared with the sham-operation group,the model group exhibited a significant reduction in TREM2,PI3K,p-PI3K,Akt,p-Akt,Bcl2 and Bcl2/Bax(P<0.05),as well as a significant increase in Bax protein expression(P<0.05);compared with the model group,the Wen-Shen-Tong-Du Decoction group showed a significant increase in TREM2,PI3K,Akt,p-Akt,Bcl2,and Bcl2/Bax(P<0.05),as well as a significant decrease in Bax protein expression(P<0.05).To conclude,Wen-Shen-Tong-Du Decoction may activate the PI3K/Akt signaling pathway by up-regulating the expression of TREM2 protein in microglia,and then inhibit neuronal apoptosis,thus exerting neuroprotective effects and promoting the repair of spinal cord injury.