对肾上腺素性心肌缺血模型大鼠相关指标的探讨

目的进一步探讨客观评价大鼠心肌缺血模型的指标。方法观察皮下注射10mg kg异丙肾上腺素(ISO)造成SD大鼠心肌缺血性损伤模型后心电图的变化、检测血清中肌酸激酶(CK)、乳酸脱氢酶(LDH)、游离脂肪酸(FFA)以及心肌组织的坏死面积、超氧化物歧化酶(SOD)、丙二醛(MDA)含量的变化。结果腹腔注射ISO后30s,大鼠心电图的J点开始降低,2min后缓慢回升,但20min后仍未回复到原来的水平,而且20min内各时间点与给药前比较,模型对照组大鼠的J点与生理盐水对照组比较,差异有显著性(P<0.05);T波则在注射异丙肾上腺素30s后开始下降,10min内两组的T波一直保持显著差异(P<0.05),而且注射异丙肾上腺素后30s(P<0.01)以及5min(P<0.05)与给药前比较,T波均有显著差异;模型对照组大鼠血清中CK、LDH、FFA以及心肌组织中MDA浓度均显著高于生理盐水对照组,心肌坏死面积与这些指标呈正相关关系,心肌组织中SOD浓度显著低于生理盐水对照组。结论J点可以作为评价此种动物模型的主要指标,T波可以作为辅助指标,应重点观察20min内心电图的变化;可以选择CK、LDH、FFA、SOD、MDA等生化指标以及心肌坏死面积等来探讨抗心肌缺血药物的作用机理。

Exploration on Relevant Indexes in Isoprenaline-induced Rat Myocardial Ischemia Models

Objective To further discuss the indexes which can be used to objectively appraise the rat myocardial ischemia models. Methods To observe the effects of intraperitoneally injected isoprenaline in a dose of 10 mg/kg b.w. on the changes of electrocardiogram (ECG) and to assay the serum content of creatine kinase (CK), lactate dehydrogenase (LDH) and free fatty acids (FFA), and to measure the necrotic area of myocardia, the superoxide dismutase (SOD) and malondialdehyde (MDA) contents in cardiac muscle of Sprague_Dawley rats, compared with those of control rats received saline injection. Results The J point of ECG in myocardial ischemia model rats descented 30s after injection of isoprenaline (10 mg/kg) and recovered slowly after 2 min, but could not return to the original state within 20 minutes, and the J points at each time points within 20 min were significantly different from those in control rats ( P <0 05). T waves of ECG in myocardial ischemia model rats were also decreased since 30 s after s.c. injection of isoprenaline and were significantly different from those in control rats within 10 min. ( P <0 05). T waves of ECG in myocardial ischemia model rats at 30 s and 5 min after s.c. injection of isoprenaline were significantly different from those of control rats ( P <0 01 and P <0 05, respectively). The content of CK, LDH, FFA in serum and MDA in cardiac muscle of model rats were significantly higher than those of the control rats and the area of myocardial necrosis was positively correlated with those alterations. But SOD in cardiac muscle was negatively correlated with them. Conclusions The J point of ECG can be considered as a main index and T waves as an adjuvant index to evaluate this animal model, and the changes should be monitored within 20 min after drug administration. Some biochemical indexes such as CK, LDH, FFA, SOD or MDA are also helpful in studying the mechanisms and effects of anti_myocardial ischemia drugs.