不同浓度的亚甲蓝对离体蟾蜍心肌缺血的保护作用

目的：探讨不同浓度的亚甲蓝对离体蟾蜍心肌缺血再灌注后心脏功能活动的影响。方法：取80只蟾蜍采用斯氏离体蛙心灌流方法,建立心肌缺血模型,随机分为4组,分别用低剂量（0.05%）、中剂量（0.1%）、高剂量（0.2%）和生理盐水进行处理,在用药后1、2、3、4、5、7 min各时间点观察其心率、心肌收缩力、心肌收缩最大速率（dp/dt）max和心肌舒张最大速率（-dp/dt）max的变化。结果：低剂量组（0.05%）、中剂量（0.1%）组与生理盐水组比较心肌收缩力差异有统计学意义（P〈0.01,P〈0.05）、在各时间点低剂量组与生理盐水组比较心肌收缩最大速率（dp/dt）max和心肌舒张最大速率（-dp/dt）max差异有统计学意义（P〈0.05）。结论：中低剂量的亚甲蓝对缺血的离体蟾蜍心脏活动具有不同程度改善功能。

The protection effects of methylene blue on isolated toad heart with myocardial ischemia

Objective：To explore the effects of methylene blue（MB） of different concentrations on isolated heart function and activities after the myocardial ischemia reperfusion in toads.Methods：Myocardial ischemia reperfusion model was established by Straub＇s method.Eighty toads were randomly divided into four groups：MB treatment group of low-dose（0.05%）,middle-dose（0.1%） group,high-dose（0.2%） group and normal saline group.Changes on heart rate,myocardial contractility,maximum rate of myocardial contraction（＋dp/dtmax） and maximum rate of myocardial relaxation（-dp/dtmax） were observed at 1,2,3,4,5,7 min after treatment respectively.Results：There was significant difference in myocardial contractility among the low-dose MB group（0.05%）,middle-dose MB group（0.1%） and normal saline group（P0.01 or 0.05）.Markedly difference was also found in maximum rate of myocardial contraction and relaxation（±dp/dtmax） between the low-dose MB group（0.05%） and normal saline group（P0.05） in corresponding time points.Conclusion：Low or middle dose of MB improved isolated heart activities in toads with myocardial ischemia.