左西孟旦调控磷酸酶基因蛋白激酶B通路降低猪冠状动脉微栓塞后心肌细胞的凋亡

Levosimendan reduces apoptosis of myocytes in swine after coronary microembolization by regulating the PTEN/Akt pathway

目的探讨左西孟旦能否通过调控磷酸酶基因(PTEN)/蛋白激酶B(Akt)通路降低猪冠状动脉微栓塞(coronary microembolization,CME)后心肌细胞的凋亡.方法选择12周龄健康小型猪1 5只,随机分为假手术组、CME组、左西孟旦组,每组5只.猪CME模型建立,观察12h进行心脏超声检测,评估心功能的指标包括左心室舒张末期内径(LVEDD)、LVEF、心排血量及左心室短轴缩短率(LVFS).TUNEL染色检测心肌细胞凋亡,Western blot检测PTEN、Akt、磷酸化Akt、半胱氨酸天冬氨酸蛋白酶3(caspase-3)、活化caspase-3表达水平.结果与假手术组比较,CME组LVEDD明显升高,CME组和左西孟旦组LVEF、LVFS及心排血量明显降低,差异有统计学意义(P<0.05);与CME组比较,左西孟旦组LVEF、LVFS及心排血量明显升高,LVEDD明显降低,差异有统计学意义(P<0.05).与假手术组比较,CME组心肌细胞PTNE和活化caspase-3表达明显升高,CME组磷酸化Akt表达明显降低,差异有统计学意义(P<0.05).与CME组比较,左西孟旦组心肌细胞PTNE和活化caspase-3表达明显降低(0.236±0.095 vs 0.485±0.135,0.364±0.196 vs 0.725±0.436,P<0.05),磷酸化Akt表达明显升高(0.972±0.467 vs 0.723±0.265,P<0.05).结论左西孟旦预处理可明显减少CME后心肌细胞凋亡并改善心功能,其机制可能是通过调控PTEN/Akt通路来实现.

Objective To study whether levosimendan can reduce the apoptosis of myocytes in swine after coronary microembolization(CME)by regulating the PTEN/Akt pathway.Methods Fifteen swines aged 12 weeks were randomly divided into sham operation group,CME group and levosimendan treatment group(5 in each group).A CME model of swine was established.The animals were monitored for 12 h by echoultrasonography for the measurement of LVEDD,LVEF, cardiac output and LVFS.The apoptosis of myocytes in swine was assayed with TUNEL staining. The expressions of PTEN,Akt,p-Akt, activated caspase-3 were detected by Western blot. Results The LVEDD was significantly longer in CME group than in sham operation group(P < 0.05).The LVEF,LVFS and cardiac output were significantly lower in CME group and levosimendan treatment group than in sham operation group(P <0.05).The LVEF,LVFS and cardiac output were significantly higher while the LVEDD was significantly shorter in levosimendan treatment group than in CME group(P <0.05).The expression levels of PTNE and activated caspase-3 were significantly higher while those of p-Akt were significantly lower in CME group than in sham operation group(P <0.05).The expression levels of PTNE and activated caspase-3 were significantly lower while those of p-Akt were significantly higher in levosimendan treatment group than in CME group(0.236±0.095 vs 0.485±0.135,0.364±0.196 vs 0.725±0.436,P < 0.05;0.972±0.467 vs 0.723±0.265,P <0.05).Conclusion Pretreatment with levosimendan can effectively reduce the apoptosis of cardiomyocytes and improve the cardiac function after CME by regulating the PTEN/Akt pathway.