槲皮素通过AKT/FOXO3信号通路保护糖尿病大鼠心肌细胞

Protection of quercetin on myocardial cell in diabetic rats through AKT/FOXO3 signaling pathway

目的:探讨槲皮素对糖尿病大鼠心肌细胞的保护作用及其机制。方法:将雄性SD大鼠随机分为对照组、糖尿病组、槲皮素低剂量(50 mg/kg)干预组和槲皮素高剂量(100 mg/kg)干预组。除对照组外其余各组均注射链脲佐菌素(STZ)构建1型糖尿病大鼠动物模型,槲皮素干预组分别给予低剂量(50 mg/kg)和高剂量(100 mg/kg)槲皮素灌胃。槲皮素灌胃1个月后,采用超声心动图检测大鼠心功能;采用TUNEL染色法检测大鼠心肌组织细胞凋亡水平;采用蛋白质印迹法检测大鼠心肌组织B淋巴细胞瘤因子相关X蛋白(BAX)、B淋巴细胞瘤-2(BCL-2)、磷酸化蛋白激酶B(pAKT)、蛋白激酶B(AKT)、磷酸化叉头核蛋白O3(pFOXO3)、叉头核蛋白O3(FOXO3)表达;采用实时荧光定量PCR检测大鼠心肌组织Bax和Bcl-2的mRNA水平。结果:糖尿病组心功能指标较对照组显著降低(P<0.05),但给予槲皮素干预后,心脏射血分数和短轴缩短率有明显改善(P<0.05)。糖尿病组心肌细胞凋亡率高于对照组(P<0.05),槲皮素干预后均明显改善(P<0.05),槲皮素低剂量干预组与高剂量干预组间无明显差异(P>0.05)。糖尿病组心肌组织Bax mRNA及蛋白水平均高于对照组(P<0.05),槲皮素干预后明显下降(P<0.05);糖尿病组Bcl-2 mRNA及蛋白水平均低于对照组(P<0.05),槲皮素干预后明显升高(P<0.05)。糖尿病组pAKT及pFOXO3蛋白表达较对照组明显下降(P<0.05),槲皮素干预后均明显升高(P<0.05),AKT及FOXO3在各组间表达无明显差异(P>0.05)。结论:槲皮素通过激活AKT/FOXO3信号通路减少糖尿病大鼠心肌细胞凋亡,从而改善心功能。

Objective:To investigate the protective effects and mechanisms of quercetin on myocardial cell in diabetic rats.Methods:Male Spregue-Dawley rats were randomly divided into four groups:control group,diabetes group,intervention group with low dose quercetin(50 mg/kg gavage),intervention group with high dose quercetin(100 mg/kg gavage).All groups received streptozocin(STZ)by intraperi-toneal injection to induce type 1 diabetes mellitus model expect for control group.After gavage for 1 month,cardiac functions were tested by echocardiography.The ratios of cardiomyocyte apoptosis were detected by TUNEL staining.The protein expression of B-cell lymphoma-2 associated X(BAX),B-cell lymphoma-2(BCL-2),phosphorylated protein kinase B(pAKT),AKT,phosphorylated forkhead box O3(pFOXO3),FOXO3 were tested by Western blotting.The mRNA levels of Bax and Bcl-2 were tested by quantitative real-time PCR.Results:The cardiac function of diabetes group reduced compared to control group,but ejection fraction and fractional shortening increased in intervention group with low dose quercetin and intervention group with high dose quercetin(P<0.05).The ratios of cardiomyocyte apoptosis in diabetes group were higher than control group(P<0.05),but it decreased in intervention group with low dose quercetin and intervention group with high dose quercetin(P<0.05).There were no obvious changes between intervention group with low dose quercetin and intervention group with high dose quercetin(P>0.05).The mRNA and protein expression of Bax in diabetes group were higher than that in control group(P<0.05),but they reduced in intervention group with low dose quercetin and intervention group with high dose quercetin compared to diabetes group(P<0.05).The mRNA and protein expression of Bcl-2 in diabetes group were lower than control group(P<0.05),but they increased in intervention group with low dose quercetin and intervention group with high dose quercetin compared to diabetes group(P<0.05).The protein expression of pAKT and pFOXO3 in diabetes group were lower than control group(P<0.05),but they increased in intervention group with low dose quercetin and intervention group with high dose quercetin(P<0.05),there were no obvious changes in AKT and FOXO3 between four groups(P>0.05).Conclusion:Quercetin can reduce apoptosis of myocardial cell in diabe-tic rats through activating AKT/FOXO3 signaling pathway,thus restore the cardiac function.