梯度降压缺氧预激对小鼠心肌缺氧耐受性影响及其机制初探

EFFECTS OF REPETITIVE HYPOXIA PRECONDITIONING ON MYOCARDIAL TOLERANCE TO HYPOXIA IN MICE

目的：探讨反复缺氧预激对小鼠缺氧耐受性的影响及其可能机制。方法：用正常小鼠及经５次梯度降压缺氧预激小鼠分别制备血浆及心肌匀浆。将来自正常小鼠及预激小鼠的血浆分别注入两组正常小鼠腹腔（Ｎｏｎ－ＰＰ组和ＰＰ组），将来自正常小鼠及预激小鼠的心肌匀浆分别注入另两组正常小鼠腹腔（Ｎｏｎ－ＰＨ组和ＰＨ组）。各小鼠分别于注射后３０ｍｉｎ置于２８．７ｋＰａ低压缺氧环境下测心电活动时间（ＣＥＡＴ）。结果：ＰＨ组ＣＥＡＴ比Ｎｏｎ－ＰＨ组延长１．８０倍（Ｐ＜０．０１），ＰＰ组ＣＥＡＴ比Ｎｏｎ－ＰＰ组延长１．２９倍（Ｐ＜０．０１）。结论：反复梯度降压缺氧预激能明显增强小鼠心肌的缺氧耐受性。

Objective:This study was to explore effects of repetitive hypoxic preconditioning on the myocardial tolerance to hypoxia of mice and its possible mechanism.Methods:Used normal mice and the mice preconditioned by grade-declined hypoxia for five times to prepare plasm and myocardial homogenate respectively,then injected plasm from normal and preconditioned mice p.i.into two groups of normal mice (Non-PP group and PP group)respectively,injected homogenate from normal and preconditioned mice p.i.into two other groups of normal mice (Non-PP group and PP group) respectively,and observed the change of cardial electron activation time (CEAT)30min after injection under the air pressure of 28 7kPa.Results:The CEAT of PH group and PP group increased up to 1 8-fold and 1 29-fold respectively comparde with the corresponding Non-PH group and Non-PP group.Conclusion:Repetitive hypoxic preconditioning under grade-declined air pressure can improve the myocardial tolerance to hypoxia in mice.The possible mechanisms might be that repetitive hypoxia preconditioning make heart of produce some adaptive changes and some protective and transferable materials.