瑞马唑仑预先给药对小鼠丘脑出血性脑损伤的影响

Effect of remimazolam pretreatment on brain injury following thalamic hemorrhage in mice

目的评价瑞马唑仑预先给药对小鼠丘脑出血性脑损伤的影响。方法清洁级健康成年CD1雄性小鼠60只,体重25~30 g,7~8周龄,采用随机数字表法分为3组(n=20):假手术组(Sham组)、脑损伤组(BI组)和瑞马唑仑预先给药组(Rem组)。Rem组尾静脉注射瑞马唑仑25 mg/kg;Sham组和BI组尾静脉注射等容量生理盐水。10 min后向单侧腹后外侧核和腹后内侧核显微注射Ⅳ型胶原酶0.01 U/10 nl,制备小鼠丘脑出血性脑损伤模型。造模后6 h时处死大鼠,取脑组织,测定湿重/干重(W/D)比值;取海马组织,HE染色后计数海马齿状回区存活神经元,透射电镜下观察海马组织超微结构,TUNEL法进行海马CA1区凋亡神经元计数,采用RT-PCR法测定海马组织CCAAT增强子结合蛋白同源蛋白(CHOP)、活化的转录因4(ATF4)和X-盒结合蛋白-1(XBP1)的mRNA表达水平,采用Western blot法测定海马组织CHOP、Bcl-2、Bax及caspase-3的表达水平。结果与Sham组比较,BI组和Rem组脑组织W/D比值和海马CA1区凋亡神经元计数升高,海马齿状回区存活神经元计数降低,海马组织CHOP、ATF4和XBP1的mRNA表达上调,CHOP、caspase-3和Bcl-2表达上调,Bax表达下调(P<0.05);与BI组比较,Rem组脑组织W/D比值和海马CA1区凋亡神经元计数降低,海马齿状回区存活神经元计数升高,海马组织CHOP、ATF4和XBP1的mRNA表达下调,CHOP、caspase-3和Bcl-2表达下调,Bax表达上调(P<0.05)。结论瑞马唑仑预先给药可减轻小鼠丘脑出血性脑损伤,其机制可能与抑制海马内质网应激诱导的细胞凋亡有关。

Objective To evaluate the effect of remimazolam pretreatment on brain injury following thalamic hemorrhage in mice.Methods Sixty clean-grade healthy adult CD1 male mice,weighing 25-30 g,aged 7-8 weeks,were divided into 3 groups(n=20 each)by using a random number table method:sham operation group(Sham group),brain injury group(BI group)and remimazolam pretreatment group(Rem group).Remimazolam 25 mg/kg was intravenously injected via the tail vein in group Rem.and the equal volume of normal saline was given instead in Sham group and BI group.Ten min later,type Ⅳ collagenase 0.01 U/10 nl was microinjected into unilateral ventroposterolateral nucleus and ventromedial nucleus to develop a mouse model of brain jury induced by thalamic hemorrhage.The rats were sacrificed at 6 h after developing the model,brain tissues were taken for measurement of the wet/dry weight(W/D)ratio,and hippocampal tissues were taken and stained with haematoxylin and eosin for determination of the count of the viable neurons in the hippocampal dentategyrus area,count of apoptotic neurons in the hippocampal CA1 region(by TUNEL),expression of CCAAT/enhancer-binding protein homologous protein(CHOP),activating transcription factor 4(ATF4)and X-box binding protein-1(XBP1)mRNA(by real-time polymerase chain reaction)and expression of CHOP,Bcl-2,Bax and caspase-3(by Western blot)and for microscopic examination of ultrastructure of hippocampal tissues(with a transmission electron microscope).Results Compared with group Sham,the W/D ratio of brain tissues and count of apoptotic neurons in the hippocampal CA1 area were significantly increased,the count of viable neurons in the hippocampal dentate gyrus was decreased,the expression of CHOP,ATF4 and XBP1 mRNA in hippocampal tissues was up-regulated,the expression of CHOP,caspase-3 and Bcl-2 was up-regulated,and the expression of Bax was down-regulated in BI and Rem groups(P<0.05).Compared with group BI,the W/D ratio of brain tissues and count of apoptotic neurons in the hippocampal CA1 area were significantly decreased,the number of viable neurons in the hippocampal dentate gyrus was increased,the expression of CHOP,ATF4 and XBP1 mRNA in hippocampal tissues was down-regulated,the expression of CHOP,caspase-3 and Bcl-2 was down-regulated,and the expression of Bax was up-regulated in group Rem(P<0.05).Conclusion Remimazolam pretreatment can reduce the brain injury following thalamic hemorrhage in mice,and the mechanism may be related to inhibition of cell apoptosis induced by endoplasmic reticulum stress in hippocampus.