右美托咪定预处理对红藻氨酸诱导癫痫小鼠海马神经元的保护作用

Role of preconditioning with dexmedetomidine in protecting hippocampal neurons in kainic acid induced epilepsy mice

目的构建红藻氨酸诱导的癫痫小鼠模型,探讨右美托咪定(dexmedetomidine,Dex)预处理对癫痫小鼠海马神经元的保护作用。方法30只雄性ICR小鼠,随机分为对照组、模型组和Dex预处理组各10只。对照组和模型组每日腹腔注射50μg/kg生理盐水,Dex预处理组每日腹腔注射50μg/kg Dex,持续7 d;第8天对照组单次腹腔注射25 mg/kg生理盐水,模型组和Dex预处理组单次腹腔注射25 mg/kg红藻氨酸构建癫痫模型。造模成功后,采用FJB荧光染色法检测3组小鼠海马组织FJB阳性细胞数,采用免疫组织化学法检测小鼠海马组织神经元特异性核蛋白(neuron-specific nuclear protein,NeuN)表达的平均光密度(average optical density,AOD)值,采用Western blot法检测小鼠海马组织离子钙结合衔接分子1(ionized calcium binding adaptor molecule-1,Iba1)、胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、cleaved caspase-3、白细胞介素-1β(interleukin-1β,IL-1β)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)蛋白相对表达量。结果模型组海马组织FJB阳性细胞数[(87.88±13.01)个]多于对照组[(0.00±0.00)个]、Dex预处理组[(28.34±8.90)个](P<0.05),NeuN表达的AOD值(0.51±0.18)低于对照组(1.89±0.52)、Dex预处理组(1.68±0.43)(P<0.05),Iba-1(1.79±0.32)、GFAP(2.85±0.29)、cleaved caspase-3(2.32±0.53)、IL-1β(2.59±0.65)、TNF-α(2.29±0.71)蛋白相对表达量均高于对照组(0.31±0.08、0.42±0.09、0.33±0.08、0.42±0.10、0.57±0.13)、Dex预处理组(0.49±0.13、1.21±0.19、0.81±0.15、0.86±0.16、0.86±0.21)(P<0.05);Dex预处理组海马组织FJB阳性细胞数多于对照组(P<0.05),NeuN表达的AOD值低于对照组(P<0.05),Iba-1、GFAP、cleaved caspase-3、IL-1β、TNF-α蛋白相对表达量均高于对照组(P<0.05)。结论Dex预处理可通过减轻海马神经元凋亡及炎性反应,对红藻氨酸诱导的癫痫小鼠海马神经元起保护作用。

Objective To construct kainic acid(KA)induced epilepsy mouse models and to investigate the role of dexmedetomidine(Dex)preconditioning in protecting hippocampal neurons in KA induced epilepsy mice.Methods Thirty male ICR mice were randomly divided into control group,model group and Dex preconditioning group,with 10 mice in each group.Control group and model group were intraperitoneally injected with 50μg/kg normal saline and Dex preconditioning group was intraperitoneally injected with 50μg/kg Dex daily for 7 days.By day 8,control group was injected with 25 mg/kg normal saline,and model group and Dex preconditioning group were injected with 25 mg/kg red algine to establish epilepsy models.After successful modeling,FJB fluorescence staining was used to detect the number of FJB positive cells in the hippocampal tissues,immunohistochemistry was used to detect the average optical density(AOD)of neuron-specific nuclear protein(NeuN),and Western blot was used to detect the relative expressions of ionized calcium binding adaptor molecule-1(Iba1),glial fibrillary acidic protein(GFAP),cleaved caspase-3,interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α).Results The number of FJB positive cells was larger in model group(87.88±13.01)than that in control group(0.00±0.00)and Dex preconditioning group(28.34±8.90)(P<0.05),and larger in Dex preconditioning group than that in control group(P<0.05).The AOD value of NeuN expression was lower in model group(0.51±0.18)than that in control group(1.89±0.52)and Dex preconditioning group(1.68±0.43)(P<0.05),and lower in Dex preconditioning group than that in control group(P<0.05).The relative expressions of Iba-1,GFAP,cleaved caspase-3,IL-1βand TNF-αwere higher in model group(1.79±0.32,2.85±0.29,2.32±0.53,2.59±0.65,2.29±0.71)than those in control group(0.31±0.08,0.42±0.09,0.33±0.08,0.42±0.10,0.57±0.13)and Dex preconditioning group(0.49±0.13,1.21±0.19,0.81±0.15,0.86±0.16,0.86±0.21)(P<0.05),and higher in Dex preconditioning group than those in control group(P<0.05).Conclusion Dex preconditioning can protect the hippocampal neurons in KA induced epilepsy mice by reducing the apoptosis of hippocampal neurons and inflammatory response.