1,6-二磷酸果糖预先给药对大鼠急性心肌缺血时缝隙连接蛋白43的影响

Effect of fructose-1,6-dephosphate pretreatment on myocardial connexin43 in a rat model of acute myocardial ischemia

目的 探讨1,6-二磷酸果糖（FDP）预先给药对大鼠急性心肌缺血时缝隙连接蛋白43（Cx43）的影响.方法 健康成年雄性SD大鼠36只,体重220～280 g,周龄8～12周,随机分为3组（n=12）：假手术组（S组）开胸前即刻经股静脉注射生理盐水5 ml,仅游离血管穿线不结扎;缺血组（I组）在心肌缺血前10 min经股静脉注射生理盐水5 ml;FDP组（F组）在心肌缺血前10 min经股静脉注射10%FDP 100 mg/kg （5 m1）.I组和F组采用结扎冠状动脉左前降支30 min的方法制备大鼠急性心肌缺血模型,记录结扎后30 min内心律失常的发生情况,评价心律失常严重程度.结扎30 min后快速摘取心脏.测定左心室面积（LVA）,缺血区面积（AAR）和梗死区面积（IA）,计算AAR/LVA和IA/AAR.测定心肌Cx43表达.结果 与S组比较,I组和F组心肌Cx43表达下调,心律失常严重程度升高（P〈0.05）.与I组比较,F组心肌Cx43表达上调,IA/AAR降低,心律失常严重程度降低（P〈0.05）.结论 FDP预先给药可减轻大鼠急性心肌缺血损伤,其机制与上调心肌Cx43表达有关.

Objective To investigate the effect of fructose-1,6-diphosphate （FDP） pretreatment on myocardial connexin43 （Cx43） in a rat model of acute myocardial ischemia.Methods Thirty-six male 8-12 week old SD rata weighing 220-280 g were randomly divided into 3 groups （n=12 each）：group Ⅰ sham operation （group S）;group Ⅱ ischemia（group Ⅰ）and group Ⅲ FDP＋ischemia（group F）.The animals were anesthetized with intraperitoneal 10%chloral hydrate 40 mg/100 g,tracheostomized and mechanically ventilated.Acute myocardial ischemia was induced by occlusion of left anterior descending coronary artery for 30 min.Myocardial ischemia was;verified by elevation of S-T segment on ECG.In group F FDP 100 mg/kg was injected iv at 10 min before ischemia.Arrhythmia was recorded within 30 min after occlusion and the severity of arrbythmia was aggesged.The hearts were removed after 30 min myocardial ischemia.The Left ventricle area （LVA）,myocardial infarct area （IA） and area at risk （AAR） were measured and AAR/LVA and IA/AAR ratios were calculated.The expression of myocardial Cx43 protein was determined by immuno-histochemestry and analysis of mean optical density.Results The severity of arrhythmia was significantly higher in group F and I than in gropu S.while lower in group F than in group I（P〈0.05）.The IA,IA/AAR ratio was significantly lower in group F than in group I.The myocardial Cx43 protein expression was down-regulated in group I and F as compared with group S.and was significantly lower in group I than in group F.Conclusion FDP pretreatment can protect myocardium against acute ischemia by up-regulation of myocardial Cx43 expression.