右美托咪定预处理对小鼠肺缺血-再灌注损伤时微小RNA-210表达的影响

Effect of dexmedetomidine preconditioning on expression of microRNA-210 during pulmonary ischemia-reperfusion injury in mice

目的 观察右美托咪定（Dex）预处理对小鼠肺缺血/再灌注损伤（PIRI）时微小RNA（miRNA,miR）-210表达的影响.方法 采用C57BL/6J小鼠在体单侧原位PIRI模型.按照随机数字表法将小鼠45只随机分为3组,每组15只：假手术组（Sham组）、缺血-再灌注组（I/R组）和Dex预处理组（Dex组）.Dex组于缺血前30 min经腹腔注射Dex 25 μg/kg,Sham组和I/R组分别经腹腔注射等量生理盐水.各组实验结束后处死小鼠,留取左肺,分别检测肺组织湿/干重比（W/D）和总肺水含量（TLW）,光镜观察肺组织形态学并测定肺泡损伤率（IAR）,电镜观察肺组织超微结构改变,实时荧光定量聚合酶链反应（FQ-PCR）法检测肺组织miR-210表达,原位缺口末端标记法（TUNEL）检测肺组织细胞凋亡指数（AI）.结果 与Sham组[4.34 ±0.25、3.33 ±0.24、（5.73±1.96）％、（4.86±0.97）％]比较,I/R小鼠组肺组织W/D （5.95 ±0.43）、TLW （4.68±0.42）、IAR[（40.47±5.93）％]和AI[（35.36±5.93）％]均升高（P＜0.05）,肺组织miR-210表达（4.73±0.78比1.07 ±0.38）上调（P＜0.05）,肺组织形态学结构及超微结构均发生损伤.与I/R组比较,Dex组肺组织W/D （5.36 ±0.14）、TLW （4.25 ±0.18）、IAR[（14.72±3.57）％]和AI[（16.49±2.51）％]均降低（P＜0.05）,肺组织miR-210表达（1.53 ±0.45比4.73 ±0.78）下调（P＜0.05）,肺组织形态学结构及超微结构损伤均减轻.结论 Dex预处理可能通过下调肺组织miR-210的表达,减少肺组织细胞凋亡,从而减轻小鼠I/R所致的急性肺损伤.

Objective To investigate the effect of dexmedetomidine （Dex） preconditioning on the expression of microRNA-210 （miR-210） during pulmonary ischemia-reperfusion injury （PIRI） in mice.Methods Mouse model of PIRI in situ was established with unilateral lung in vivo.Forty-five experimental mice were randomly allocated into three groups：sham operation group （sham group）,ischemia-reperfusion group （I/R） and Dex preconditioning group （Dex group）,15 mice per group.Dex was injected intraperitoneall with 25 μg/kg at 30 min before ischemia in Dex group.The equal volume of normal saline was injected intraperitoneall in sham group and I/R group,respectively.Mice were euthanized after experimental time out,and left lung tissue was extracted.Wet lung weight and dry lung weight （W/D） and total lung water content （TLW） were tested.Morphology of lung tissue was observed and injured alveolar rate （IAR） was tested by light microscope,and ultrastructure of lung tissue was observed by electron microscope.The expression of miR-210 was detected by real-time fluorescent quantitative polymerase chain reaction （FQ-PCR）.Apoptosis of lung tissue was determined by terminal-deoxynucleoitidyl transferase mediated nick end labeling （TUNEL） me（）nod.Results Compared to sham group [4.34 ±0.25,3.33 ±0.24,（5.73 ±1.96）%,（4.86±0.97）%],W/D （5.95 ±0.43）,TLW （4.68 ±0.42）,IAR [（40.47 ± 5.93） %] and AI[（35.36 ± 5.93） %] of the lung tissue were all significantly increased （P 〈 0.05）,the expression of miR-210 （4.73 ± 0.78 vs.1.07 ± 0.38） was significantly up-regulated （P 〈 0.05）,injury of morphology and ultrastructure of the lung tissue was alleviated in I/R group.Compared to I/R group,W/D （5.36 ±0.14）,TLW （4.25 ±0.18）,IAR [（14.72±3.57）%] and AI [（16.49± 2.51）%] of the lung tissues were all significantly reduced （P 〈 0.05）,the expression of miR-210 （1.53 ± 0.45 vs.4.73 ± 0.78） was significantly down-regulated （P 〈 0.05）,the injury of morphology and ultrastructure of lung tissue was alleviated in Dex group.Conclusion Dex preconditioning maybe alleviate lung injury induce by I/R in mice by down-regulating the expression of miR-210 of lung tissue and decreasing pneumonocyte apoptosis.