磷酸肌酸对异丙肾上腺素致大鼠急性心肌缺血的保护作用

Protective effects of phosphocreatine against acute myocardial ischemia induced by isoprenaline in rats

目的：探讨磷酸肌酸（ Pcr）对异丙肾上腺素（ ISO）诱导的大鼠急性心肌缺血的保护作用。方法 SD雄性大鼠48只，体质量390～460 g，随机分为四组（n＝12）：假手术组、模型组、低剂量Pcr组和高剂量Pcr组。模型组和Pcr组采用皮下多点注射ISO方法（10 mg／kg）制作大鼠急性心肌缺血模型。 Pcr组提前30 min给予Pcr，剂量分别为300 mg／kg和500 mg／kg。假手术组大鼠皮下注射等剂量生理盐水（10 mg／kg）。给药后30 min、60 min记录四组心电图；取血检测血清门冬氨酸氨基转移酶（AST）、乳酸脱氢酶（LDL）、磷酸肌酸激酶（CK）和磷酸肌酸激酶同工酶（ CK－MB）；常规心脏冰冻切片，HE染色观察心肌形态学变化。结果模型组大鼠30 min心电图ST－T升高，60 min升高更明显。 Pcr组心电图升高的ST－T在30 min、60 min均较模型组降低，高剂量Pcr组降低更显著。 Pcr组血清AST、LDH、CK及CK－MB显著低于模型组，且高剂量Pcr组血清酶学降低更明显（P＜0．01）。模型组心肌纤维排列紊乱，部分溶解，较多空泡。 Pcr组心肌纤维基本完整，少量空泡。结论外源性磷酸肌酸对异丙肾上腺素诱导的大鼠急性心肌缺血有保护作用。

Objective To investigate the protective effects of phosphocreatine （Pcr） against acute myocardial ischemia induced by isoprenaline （ ISO） in rats.Methods Forty-eight male SD rats weighting 390~460 g were randomly divided into four groups （n=12）：sham group, ISO group, low-dose-Pcr （300 mg/kg） group and high-dose-Pcr （500 mg/kg） group.ISO rat model was made with subcutaneous ISO （10 mg/kg） multi-point injection method.Rats in Pcr groups were given Pcr 30 minutes ahead of ISO injection.While sham group was injected with physiological saline only. 30 minutes and 60 minutes electrocardiograms （ ECG） were recorded respectively after ISO injection.Serum level of aspertate aminotransferase （AST）, lactate dehydrogenase （LDH）, creatine kinase （CK） and creatine phosphate kinase isoenzyme （ CK-MB） were tested and heart frozen sections were performed. Results The ST-T of ECG in ISO group elevated in 30 minutes and became higher in 60 minutes. Compared with ISO group, the elevation in low-dose-Pcr group was significantly reduced in both 30 and 60 minutes after ISO injection and the significance became more obvious in high-dose-Pcr group. At the same time, serum level of AST, LDH, CK and CK-MB was significantly reduced in two Pcr groups, especially in high-dose-Pcr group, compared with ISO group （P〈0.01）.Frozen sections in ISO group exhibited irregularly arranged myocardial fibers, mild myolysis and sever cavitation.However, most of the myocardial fibers were integrated and cavitation was less severe after Pcr treatment. Conclusion The exogenous phosphocreatine pretreatment has protective effects on the myocardium against acute ischemia in rats induced by ISO.