甘氨酸对缺氧/复氧离体大鼠心脏功能的作用

目的：观察甘氨酸(glycine, GLY)对缺氧/复氧离体心脏功能的影响，探讨甘氨酸对心肌缺血-再灌注 (ischemia/reperfusion, I/R)损伤的防治作用及其机制。方法：利用Langendorff灌流装置复制心肌缺氧/复氧(hypoxia/reoxygenation, H/R)模型，观察不同浓度GLY处理后心脏左室收缩压（left ventricular systolic pressure, LVSP）、左室舒张末压（left ventricular end diastolic pressure, LVEDP）、左室发展压 (left ventricular developed pressure, LVDP=LVSP-LVEDP)、左室收缩压最大上升/下降速率(the maximum rising and dropping rates of left ventricular pressure, dp/dtmax and dp/dtmin)，并在相应的时点分别测定冠脉流出液中的超氧化物歧化酶(superoxide dismutase, SOD)活性和丙二醛(malondialdehyde, MDA)的水平。结果：H/R后各时点大鼠心功能各指标均低于缺氧前；GLY处理组复氧后心功能各指标均高于H/R组，并拮抗损伤导致的SOD减少和MDA升高。结论：一定浓度的GLY能显著改善缺氧/复氧心肌的舒缩功能，其机制可能与其提高SOD活性抑制脂质过氧化反应有关。

Effect of glycine on cardiac injury induced by hypoxia-reoxygenation in isolated rat heart

AIM:To observe the effects of glycine on hypoxia-reoxygenation (H/R)-induced myocardial dysfunction, and to further clarify the protection of glycine (GLY) against myocardial ischemia/reperfusion injury and its mechanism. METHODS:A cardiac H/R model was established using a Langendorff isolated heart preparation. The left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), the maximum rising and dropping rates of left ventricular pressure (dp/dtmax and dp/dtmin) were observed. The coronary effluents at different time points were collected respectively to detect the concentration of superoxide dismutase (SOD) and malondialdehyde (MDA). RESULTS: The indexes of cardiac functions in H/R group were lower than those in other groups. After H/R, the indexes in GLY plus H/R group were higher than those in H/R group. Glycine inverted the effects of the decrease in SOD and the increase in MDA concentrations induced by H/R. CONCLUSION:Glycine ameliorates the cardiac functions under the condition of hypoxia-reoxygenation injury in isolated rat hearts. The mechanisms may be related to suppressing lipid peroxidation.