小续命汤改善心肺复苏后大鼠神经功能及脑保护作用

Study on the protective effect and mechanism of Xiaoxuming Decoction on the brain of rats after cardiopulmonary resuscitation

关键词:  小续命汤  心肺复苏  氧化应激  胞浆蛋白伴侣分子  核因子E2相关因子  血红素氧合酶1

Key words:  Xiaoxuming Decoction  cardiopulmonary resuscitation  oxidative stress  Kelch-like ECH-associated protein1  NF-E2-related factor 2  heme oxygenase-1

摘要:

[目的] 研究小续命汤对心肺复苏后大鼠的脑保护作用及机制研究。[方法] 将63只SPF级SD雄鼠按照随机数字表分为对照组（8只）和建模组（55只）。建模大鼠使用经皮心外膜电刺激法建立大鼠心脏骤停模型，将建模成功大鼠进行心肺复苏，当大鼠恢复自主循环表示大鼠心肺复苏建模成功。将建模成功的大鼠随机分为5组，小续命汤高、中、低剂量组、二甲基亚砜（DMSO）组和模型组。大鼠心肺复苏后10 min，小续命汤高、中、低剂量组灌胃300、150、75 mg/kg小续命汤。DMSO组灌胃100 mg/kg的DMSO，模型组和对照组均灌胃等体积生理盐水，每日1次，治疗7 d。治疗前后对大鼠神经功能进行评分；通过苏木精-伊红（HE）染色观察大鼠脑海马组织病变；用酶联免疫吸附实验（ELISA）测定各组大鼠脑海马组织氧化应激指标脂质过氧化物丙二醛（MDA）含量和超氧化物歧化酶（SOD）浓度；通过实时荧光定量聚合酶链式反应（RT-qPCR）检测大鼠脑海马组织胞浆蛋白伴侣分子（Keap1）、核因子E2相关因子（Nrf2）和血红素氧合酶1（HO-1）mRNA表达水平；通过蛋白免疫印迹法（Western Blot）检测大鼠脑海马组织中Keap1、Nrf2和HO-1蛋白表达水平。[结果] 大鼠治疗后神经功能评分，模型组高于对照组（P<0.05），DMSO组和小续命汤高、中、低剂量组均低于模型组（P<0.05）；对照组脑海马区组织神经元无明显病变，模型组可见神经元排列稀疏且凌乱，神经元出现明显水肿，细胞核肿胀，胞浆空泡样变，DMSO组、小续命汤高、中、低剂量组病变均出现好转；大鼠脑海马组织MDA含量模型组高于对照组（P<0.05），DMSO组和小续命汤高、中、低剂量组均低于模型组（P<0.05）；SOD含量模型组低于对照组（P<0.05），DMSO组和小续命汤高、中、低剂量组均高于模型组（P<0.05）；Keap1 mRNA和蛋白相对表达量模型组均低于对照组（P<0.05），DMSO组和小续命汤高、中、低剂量组均低于模型组（P<0.05）；Nrf2和HO-1 mRNA和蛋白相对表达量模型组高于对照组（P<0.05），DMSO组、小续命汤高、中、低剂量组均高于模型组（P<0.05）。[结论] 小续命汤可改善心肺复苏大鼠神经功能，减轻脑海马组织损伤，抑制氧化应激，推测其机制可能与激活Keap1-Nrf2/HO-1信号通路，下调Keap1 mRNA和蛋白表达，上调Nrf2和HO-1 mRNA和蛋白表达水平有关。

Abstract:

[Objective] To study the protective effect and mechanism of Xiaoxuming Decoction on the brain of rats after cardiopulmonary resuscitation.[Methods] Sixty-three male SD rats of SPF grade were randomly divided into control group (8 rats) and modeling group (55 rats). The model rats were used the percutaneous epicardial electrical stimulation method to establish a rat cardiac arrest model. The successfully modeled rats were subjected to cardiopulmonary resuscitation. When the rat resumes spontaneous circulation,the rat cardiopulmonary resuscitation model was successfully established. The rats successfully modeled were randomly divided into 5 groups:Xiaoxuming Decoction high,medium and low dose group,dimethyl sulfoxide (DMSO) group and model group. After 10 minutes of cardiopulmonary resuscitation,rats in the Xiaoxuming Decoction high,medium,and low dose group were intra-gastrically administered with 300,150,75 mg/kg Xiaoxuming Decoction. The DMSO group was intra-gastrically administered with 100 mg/kg DMSO. The model group and the control group were intra-gastrically administered with equal volume of normal saline,once a day for 7 days. Scored the neurological function of rats before and after treatment. Observe the hippocampal lesions of rat brain tissue by hematoxylin-eosin (HE) staining. The content of lipid peroxide malondialdehyde (MDA) and superoxide dismutase (SOD) in rat hippocampus tissues were measured by enzyme-linked immunosorbent assay (ELISA). Detection of cytoplasmic protein chaperones (Keap1),nuclear factor E2 related factors (Nrf2) and heme oxygenase 1 (HO-1) mRNA expression levels in rat hippocampus tissues by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). Detection of Keap1,Nrf2 and HO-1 expression levels protein in rat hippocampus tissues were detected by Western Blot.[Results] The neurological function scores of rats after treatment in the model group was higher than the control group (P<0.05),and the DMSO group and the Xiaoxuming Decoction high,medium and low dose group were lower than the model group (P<0.05). Neurons in the hippocampus of the control group without obvious lesions. In the model group,the arrangement of neurons was sparse and messy,the neurons were obviously edema,the nucleus was swollen,and the cytoplasm was vacuolated. The lesions in the DMSO group,Xiaoxuming Decoction high,medium and low dose groups were all improved. The content of MDA in the hippocampus tissues of rats in the model group was higher than that in the control group (P<0.05),while the DMSO group and Xiaoxuming Decoction high,medium and low dose group were lower than the model group (P<0.05). The SOD content in the model group was lower than that in the control group (P<0.05),and the DMSO group and the Xiaoxuming Decoction high,medium and low dose group were higher than the model group (P<0.05). The Keap1 mRNA and protein relative expression levels in the model group were lower than those in the control group (P<0.05),and the DMSO group and the Xiaoxuming Decoction high,medium and low dose group were lower than the model group (P<0.05). The Nrf2 and HO-1 mRNA and protein relative expression levels in the model group were higher than those in the control group (P<0.05),the DMSO group and Xiaoxuming Decoction high,medium and low dose group were all higher than the model group (P<0.05).[Conclusion] Xiaoxuming Decoction can improve the nerve function of cardiopulmonary resuscitation rats,reduce brain hippocampus tissue damage,and inhibit oxidative stress. It is speculated that the mechanism may be related to the activation of Keap1-Nrf2/HO-1 signaling pathway,down-regulation of Keap1 mRNA and protein expression,and up-regulation of Nrf2 and HO-1 mRNA and protein expression levels are related.