目的 研究右美托咪定（dexmedetomidine, Dex）预处理是否通过迷走神经对大鼠缺血/再灌注损伤（ischemia/reperfusion injury, I/RI）心肌产生保护作用。 方法 雄性SD大鼠50只，体重230~270 g，采用随机数字表法分为5组（每组10只）：假手术组（S组）、缺血/再灌注组（I/R组）、单侧迷走神经切断术（unilateral vagotomy, VG）+I/R组（V组）、Dex+I/R组（D组）、VG+Dex+I/R组（VD组）。 Dex经颈静脉泵注1 μg/kg 10 min，0.7 μg·kg-1·h-1 15 min。I/R模型为结扎左冠状动脉前降支30 min后恢复灌注120 min。ELISA法测定血清中IL-6、TNF-α浓度，实时荧光定量PCR（real-time quantitative PCR, qPCR）检测心肌组织中IL-6 mRNA和TNF-α mRNA表达量，伊文氏蓝及2，3，5-氯化三苯基四氮唑（2, 3, 5-triphenyl tetrazolium chloride, TTC）双染色法测定心肌缺血和心机梗死面积。 结果 与I/R组比较，D组心肌梗死面积明显减少（P<0.05），心肌组织IL-6 mRNA和TNF-α mRNA表达下调（P<0.05），血清TNF-α和IL-6浓度明显降低（P<0.05）；与D组比较，VD组以上指标均明显升高（P<0.05）。 结论 Dex预处理通过迷走神经减轻I/RI的炎症反应，从而对大鼠心肌产生保护作用。
Ｏｂｊｅｃｔｉｖｅ To determine whether dexmedetomidine(Dex) preconditioning could provide cardioprotection against ischemia/reperfusion injury(I/RI) through vagus nerve in rats. Methods Fifty male SD rats, weighing 230-270 g, were randomly divided into five groups(n=10): sham operation (group S), group I/R, unilateral vagotomy(VG)+I/R(group V), Dex+I/R (group D), VG+Dex+I/R(group VD). Dex 1 μg/kg for 10 min and 0.7 μg·kg-1·h-1 for 15 min was infused via the jugular vein. I/R model was established with ligation of left anterior descending coronary artery for 30 min followed by reperfusion for 120 min. Serum levels of IL-6 and TNF-α were measured with ELISA. The mRNA expression of IL-6 and TNF-α in myocardium was assayed with real-time quantitative PCR(qPCR). The area in heart at risk of injury was marked with Evans Blue. The infarct size was stained with 2,3,5-triphenyltetrazolium chloride. Results Compared with group I/R, the mRNA and protein levels of IL-6 and TNF-α and the infarct size were significantly decreased in group D(P<0.05). Compared with group D, these parameters were significantly increased in group VD(P<0.05). Conclusions Dex preconditioning protects heart against I/RI in rats by alleviating inflammatory response through intact vagus nerve.
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