线粒体靶向小分子IR-61改善大鼠力竭性运动心脏损伤的实验研究

目的:研究线粒体靶向七甲川花菁类荧光小分子IR-61对力竭性运动大鼠心脏损伤的影响。方法:清洁级成年雄性SD大鼠36只,随机分为3组(n=12):对照组(Ctrl组)、力竭组(EE组)、IR-61+力竭组(IR-61+EE组)。IR-61+EE组在第1、4、7日同一时间腹腔注射2 mg/kg IR-61;最后一次给药结束1 h后,两个力竭运动组进行力竭造模,在坡度为0°的动物跑步机上,先以10~15 m/min的速度令大鼠协调四肢跑步姿势,约15 min后以25~30 m/min的速度一次性跑步至力竭。以生理记录仪描记大鼠心电图,取大鼠的心肌样品,光镜观察心肌细胞损伤、透射电镜观察线粒体损伤,TUNEL法检测心肌细胞凋亡情况,ELISA法检测心肌损伤标志物,高分辨率线粒体呼吸仪测定心肌线粒体呼吸速率。结果:①与Ctrl组相比,EE组的心率增加、PR间期缩短、QRS间期延长、QTc延长、ST段明显压低(P<0.05);心肌纤维断裂明显,线粒体内室肿胀明显,线粒体嵴模糊,线粒体外膜不完整,可见大量线粒体破裂及融合;可见TUNEL染色细胞较多,呈现染色质浓缩、边缘化,核膜裂解,染色质分割成块状凋亡小体,凋亡评分增加(P<0.05);CK-MB升高、cTn-I升高、NT-proBNP升高(P<0.05);基础呼吸速率、脂肪酸氧化呼吸速率、复合物Ⅰ、Ⅱ、Ⅳ呼吸速率均有下降(P<0.05)。②与EE组相比,IR-61+EE组的心率增加、PR间期延长、QRS间期缩短、QTc缩短、ST段未见明显压低(P<0.05),心肌纤维排列疏松,未见明显断裂,线粒体内室肿胀,线粒体外膜完整,可见TUNEL染色细胞与未染色细胞,整体形态更接近Ctrl组,凋亡评分下降(P<0.05),CK-MB下降,cTn-I下降(P<0.05);脂肪酸氧化呼吸速率及复合物Ⅱ、Ⅳ呼吸速率均有提高(P<0.05)。结论:线粒体靶向七甲川花菁类荧光小分子IR-61可改善力竭运动大鼠的心电活动,减轻心肌细胞及线粒体损伤,减少心肌细胞凋亡,提高心肌线粒体能量代谢水平。

Baoyuan decoction alleviates myocardial infarction through the regulation of metabolic dysfunction and the mitochondria-dependent caspase-9/3 pathway

Objective:Baoyuan decoction(BYD)is a traditional Chinese formula with myocardial protection efficacy validated by modern pharmacological tests.The present study aimed to investigate the effect and mechanism of BYD on alleviating myocardial infarction(MI).Methods:Nuclear magnetic resonance-based serum and urinary metabolomics were employed to explore the metabolic regulation effects of BYD in rats with MI induced by left anterior descending ligation.Oxygen-glucose deprivation/recovery(OGD/R)model in H9c2 cells and multiple molecular biology approaches were used to clarify the underlying action mechanisms of BYD.Results:BYD treatment recovered the serum and urinary metabolite profiles of the MI rats toward normal metabolic status and significantly improved mitochondrial energy metabolism and apoptosis pathways perturbed by MI.Analysis of the molecular mechanism of BYD indicated that it suppressed OGD/R-induced H9c2 cell apoptosis in a concentration-dependent manner by inhibiting the mitochondria-dependent caspase-9/3-poly ADP-ribose polymerase pathway.Conclusions:Our results demonstrate that BYD protects against myocardial apoptosis via the mitochondrial metabolic and apoptosis pathways.They also provide novel insights into the clinical application of BYD for the treatment of ischemic heart diseases.

Effect of captopril on myocardial energy metabolism in chronic pressure overload rats

Objective To investigate the effects of captopril on cardiac function and levels of energy-rich phosphates in pressure overload induced left ventricular hypertrophy rats. Methods One hundred and twenty SD rats were randomly divided into three groups： sham operation group （SH group, n=40）,coarctation of abdominal aorta group （CAA group, n=40） and captopril treatment lmg~ 100g1 ~ d-1） group （CAP group, n=40）. Left ventricular end-diastolic pressure （LVEDP）, left venh-icular mass index （LVMI）, levels of energy-rich phosphates and morphological changes of the myocardial mitochondria were compared at the 62 and 82 week after operation. Results At 62 week, in CAA group, LVMI and LVEDP were increased and _ dp/dtmax was decreased, while ATP and ADP were decreased and AMP was increased （P〈0.01）. These changes were much obvious at 8th week （P〈0.01）. Compared with those of CAA group, the parameters of heart function and energy-rich phosphates （ATP, ADP, AMP, TAN） in CAP group were improved significantly（P〈0.01） at the 6th and 8th week. In CAP group, the parameters of heart function and energy-rich phosphates （ADP, AMP, TAN） were much better at 8~ week than those at 6th week. The morphological change of mitochondria was less in CAP group than that in CAA group. Conclusion Captopril significantly improves myocardial energy metabolism in pressure overload rats and protects the function of myocardial mitochondria