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目的探讨脂联素(APN)信号通路在心肌缺血预处理中的作用及机制。方法建立对照组,心肌缺血预处理(ischemic preconditioning,IPC)和缺血/再灌注(myocardial ischemia/reperfusion,MI/R)损伤小鼠模型,每组8只C57 BL/6 J小鼠。ELISA法检测血浆APN水平,超声检测心功能,TTC法观察心肌梗死面积,TUNEL染色检测心肌细胞凋亡,Western blot检测APN受体(adiponectin receptor,AdipoR),腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK)分子的表达。结果与对照组血浆APN〔(19.08±2.15)μg/ml〕相比,IPC组和MI/R组缺血30 min后血浆APN水平降低(P<0.01);与IPC组血浆APN〔(15.4±2.09)μg/ml〕相比,MI/R组血浆APN水平降至更低〔(13.95±1.75)μg/ml〕(P<0.05);与对照组左室射血分数(76.37±7.24)相比,MI/R组和IPC组左室射血分数(57.15±7.32和66.37±6.09)均降低(P<0.05);与MI/R组左室射血分数相比,IPC组左室射血分数升高(P<0.01);与对照组左室短轴缩短率(52.13±4.80)相比,MI/R组和IPC组左室短轴缩短率(37±8.14和44.9±6.52)降低(P<0.01);与MI/R组左室短轴缩短率相比,IPC组左室短轴缩短率升高(P<0.01);与对照组左室舒张末内径〔(3.13±0.59)mm〕相比,MI/R组和IPC组左室舒张末内径增加〔(3.50±0.48)mm和(3.23±0.50)mm〕(P<0.05);与MI/R组左室左室舒张末内径相比,IPC组左室舒张末内径减少(P<0.01);与对照组左室收缩末内径(1.95±0.59)mm相比,MI/R组和IPC组左室左室收缩末内径增加分别为〔(2.26±0.48)mm和(2.15±0.21)mm〕(P<0.05);与MI/R组左室左室收缩末内径相比,IPC组左室收缩末内径减少(P<0.01);与对照组心肌梗死面积相比,MI/R组和IPC组心肌梗死面积增加(45.7±3.92,40.9±4.1)(P<0.01);与MI/R组心肌梗死面积相比,IPC组心肌梗死面积增加减少(P<0.05);与对照组TUNEL阳性细胞相比,MI/R组和IPC组TUNEL阳性细胞增加(12.16±1.93和8.96±1.49)(P<0.01);与MI/R组TUNEL阳性细胞相比,IPC组TUNEL阳性细胞减少(P<0.05);与对照组Caspase-3活力〔(1.93±1.82)nmol/(h·mg)〕相比,MI/R组和IPC组Caspase-3活力增加〔(5.82±2.72和4.68±2.31)nmol/(h·mg)〕(P<0.01);与MI/R组Caspase-3活力相比,IPC组Caspase-3活力减少(P<0.05);与对照组心肌AdipoR1的表达(0.86±0.26)相比,MI/R组和IPC组心肌AdipoR1表达减少(0.57±0.15和0.72±0.22)(P<0.05);与MI/R组心肌AdipoR1的表达相比,IPC组心肌AdipoR1的表达增加(P<0.05);而AdipoR2的表达没有变化;与对照组心肌pAMPK/AMPK的表达(1.6±0.24)相比,MI/R组和IPC组心肌pAMPK/AMPK的表达减少(1.04±0.13和1.28±0.13)(P<0.05);与MI/R组心肌pAMPK/AMPK的表达相比,IPC组心肌pAMPK/AMPK的表达增加(P<0.01)。结论缺血预处理减轻心肌再灌注损伤机制部分可能在于心肌APN/AdipoR/AMPK信号通路增强。
Objective To investigate the role and mechanism of adiponectin (APN) signaling pathway in myocardial ischemic preconditioning. Methods The control group, ischemic preconditioning (IPC) and ischemia / reperfusion (MI / R) mouse models were established, each group containing 8 C57BL / 6J mice. Plasma APN levels were measured by ELISA. Cardiac function was detected by ultrasound. Area of myocardial infarction was detected by TTC method. Cardiomyocyte apoptosis was detected by TUNEL staining. Apoptosis of adiponectin receptor (AdipoR) and adenosine monophosphate activated protein kinase Protein kinase, AMPK) molecule expression. Results Compared with plasma APN in control group (19.08 ± 2.15 μg / ml), plasma APN levels in IPC group and MI / R group decreased 30 min after ischemia (P <0.01) (13.95 ± 1.75) μg / ml〕 in MI / R group (P <0.05). Compared with the control group, the left ventricular ejection fraction (76.37 ± 7.24) (P <0.05). Compared with MI / R group, the left ventricular ejection fraction in IPC group was lower than that in MI / R group (57.15 ± 7.32 and 66.37 ± 6.09) (P <0.01). Compared with the control group, the shortening rate of left ventricular short axis (52.13 ± 4.80) in MI / R group and IPC group decreased (37 ± 8.14 and 44.9 ± 6.52) P <0.01). Compared with MI / R group, the shortening rate of left ventricular short axis in IPC group was significantly higher than that in MI / R group (P <0.01). Compared with control group, the left ventricular end diastolic diameter 〔(3.13 ± 0.59) mm (3.50 ± 0.48) mm and (3.23 ± 0.50) mm respectively in MI / R group and IPC group (P <0.05). Compared with MI / R group, left ventricular end-diastolic diameter (P <0.01). Compared with control group, the mean diameter of left ventricular end-systole increased in MI / R group and IPC group (1.95 ± 0.59) mm [(2 .26 ± 0.48) mm and (2.15 ± 0.21) mm], respectively (P <0.05). Compared with MI / R group, the diameter of left ventricular end systolic diameter decreased in IPC group (P <0.01) Compared with MI / R group, myocardial infarct size in MI / R group and IPC group increased (45.7 ± 3.92, 40.9 ± 4.1) (P <0.01) (P <0.01). Compared with TUNEL positive cells in control group, TUNEL positive cells in MI / R group and IPC group increased (12.16 ± 1.93 and 8.96 ± 1.49, P <0.01) (P <0.05). Compared with the control group, Caspase-3 activity in MI / R group and IPC group was significantly lower than that in IPC group (1.93 ± 1.82 nmol / (h · mg) Compared with MI / R group, Caspase-3 activity in IPC group decreased (P <0.05) and increased (5.82 ± 2.72 and 4.68 ± 2.31 nmol / (h · mg) ; AdipoR1 expression in MI / R and IPC groups decreased (0.57 ± 0.15 and 0.72 ± 0.22) compared with that in control group (0.86 ± 0.26) (P <0.05); Compared with MI / R group, AdipoR1 Compared with the control group, the expression of AdipoR1 in IPC group was increased (P <0.05), while the expression of AdipoR2 was unchanged (P <0.05). Compared with the control group, the expression of pAMPK / AMPK (P <0.05). Compared with MI / R group and IPC group, the expression of pAMPK / AMPK was decreased (1.04 ± 0.13 and 1.28 ± 0.13, P <0.05) The expression of pAMPK / AMPK in IPC group increased (P <0.01). Conclusion The mechanism of ischemic preconditioning in reducing myocardial reperfusion injury may be partly due to the enhancement of myocardial APN / AdipoR / AMPK signaling pathway.