Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, China.
Department of Cardiology, the Second Affiliated Hospital of Kunming Medical University, Kunming 650101, China.
Biomed Pharmacother. 2020 May;125:109913. doi: 10.1016/j.biopha.2020.109913. Epub 2020 Jan 29.
Ginsenoside Rb1 (GRb1) is known to play an effective protection on myocardial infarction, yet its therapeutic mechanism on myocardial ischemia/reperfusion (I/R) injury has remained obscure. Here we sought to investigate the protective mechanism of GRb1 preconditioning on myocardial I/R injury in rats.
We report here that GRb1 preconditioning could improve myocardial I/R injury induced-cardiac functions including LVDP, -dp/dt min and + dp/dt max; however, the heart rate (HR) was maintained at a level comparable to the I/R group. Additionally, in I/R injury group given GRb1 preconditioning, release of myocardial enzymes (CK-MB and Trop l) and CtsB was decreased. Moreover, GRb1 decreased the expression of apoptotic related proteins e.g. cleaved-caspase 3; however, the ratio of Bcl-2/Bax related to anti-apoptosis was decreased. The study was extended by injecting rapamycin intraperitoneally before GRb1 pretreatment. Thus, mTOR pathway was significantly upregulated after GRb1 pretreatment when compared with I/R. Remarkably, the anti-apoptosis protection of GRb1 pretreatment was attenuated by rapamycin. Furthermore, GRb1 effectively reduced the infarct size thus supporting its role in anti-myocardial I/R injury.
It is concluded that GRb1 preconditioning can ameliorate myocardial I/R injury as manifested by the improvement of cardiac function indices; moreover, release of myocardial enzymes, namely, CK-MB, Trop l and CtsB was reduced. More importantly, we have shown that the protective effect of GRb1 against I/R injury induced cardiomyocyte apoptosis is associated with the activation of mTOR signal pathway as evident by the use of rapamycin.
人参皂苷 Rb1（GRb1）已知对心肌梗死有有效保护作用，但它对心肌缺血/再灌注（I/R）损伤的治疗机制仍不清楚。在这里，我们试图研究 GRb1 预处理对大鼠心肌 I/R 损伤的保护机制。
我们在这里报告，GRb1 预处理可以改善心肌 I/R 损伤引起的心脏功能，包括 LVDP、-dp/dt min 和+dp/dt max；然而，心率（HR）保持在与 I/R 组相当的水平。此外，在给予 GRb1 预处理的 I/R 损伤组中，心肌酶（CK-MB 和 Trop l）和 CtsB 的释放减少。此外，GRb1 降低了凋亡相关蛋白的表达，例如裂解的 caspase 3；然而，与抗凋亡相关的 Bcl-2/Bax 比值降低。该研究通过在 GRb1 预处理前腹腔内注射雷帕霉素进一步扩展。因此，与 I/R 相比，GRb1 预处理后 mTOR 通路显著上调。值得注意的是，雷帕霉素减弱了 GRb1 预处理的抗凋亡保护作用。此外，GRb1 有效减少了梗死面积，从而支持其在抗心肌 I/R 损伤中的作用。
GRb1 预处理可以改善心肌 I/R 损伤，表现为心脏功能指标的改善；此外，心肌酶，即 CK-MB、Trop l 和 CtsB 的释放减少。更重要的是，我们已经表明，GRb1 对 I/R 损伤诱导的心肌细胞凋亡的保护作用与 mTOR 信号通路的激活有关，这可以通过使用雷帕霉素来证明。
