Institute of Materia Medica, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi 710032, China; Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
Institute of Materia Medica, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
Life Sci. 2018 Jun 15;203:246-254. doi: 10.1016/j.lfs.2018.04.048. Epub 2018 Apr 26.
Apigenin-7-O-β-d-(-6″-p-coumaroyl)-glucopyranoside (APG) was considered as the major active compound derived from Clematis tangutica. Though we have demonstrated that APG exerts cardioprotective effects, the mechanism of APG-mediated cardioprotection remains largely unknown. Numerous studies indicate that endoplasmic reticulum stress (ERS) is a vital injury factor in myocardial ischemia reperfusion (MI/R). In this study, we mainly investigated whether modulation of the ERS and AMPK were involved in the cardioprotective action of APG during MI/R injury.
The perfused isolated rat heart or primary neonatal rat cardiomyocytes which exposed to APG with or else without the AMPK inhibitor Compound C was then subject to MI/R. After reperfusion, the degree of myocardial injury was assessed by using lactate dehydrogenase (LDH) release, creatine kinase (CK) release, histological examination, and TTC staining. The protein expressions of p-AMPK, AMPK, p-PERK, PERK, p-eIF2α, eIF2α, CHOP, Bax, Bcl2 and Cleaved Caspase 3 were analyzed by western blot. The cell viability was assessed by CCK-8 kit while apoptosis assessed by using TUNEL assay.
Pretreatment of APG significantly improved cardiac function and suppressed ERS through activating the AMPK signaling pathway, which could simultaneously improve cardiac function, alleviate myocardial injury, increase the cell viability and decrease apoptosis.
To conclude, APG ameliorates MI/R injury by activating the AMPK signaling pathway and relieving endoplasmic reticulum stress. APG may be a natural product with pharmacological preconditioning activity, which could do us a favor to develop more novel therapy methods to against MI/R injury in the future.
芹糖基牡荆素-7-O-β-D-（6′-对香豆酰基）-吡喃葡萄糖苷（APG）被认为是从川续断中提取的主要活性化合物。虽然我们已经证明 APG 具有心脏保护作用，但 APG 介导的心脏保护作用的机制在很大程度上尚不清楚。许多研究表明，内质网应激（ERS）是心肌缺血再灌注（MI/R）损伤的重要损伤因素。在这项研究中，我们主要研究了 ERS 和 AMPK 的调节是否参与了 APG 在 MI/R 损伤中的心脏保护作用。
用 APG 处理离体大鼠心脏或原代新生大鼠心肌细胞，然后用 AMPK 抑制剂 Compound C 处理或不处理，再进行 MI/R。再灌注后，通过测定乳酸脱氢酶（LDH）释放、肌酸激酶（CK）释放、组织学检查和 TTC 染色来评估心肌损伤程度。通过 Western blot 分析 p-AMPK、AMPK、p-PERK、PERK、p-eIF2α、eIF2α、CHOP、Bax、Bcl2 和 Cleaved Caspase 3 的蛋白表达。用 CCK-8 试剂盒评估细胞活力，用 TUNEL 测定法评估细胞凋亡。
APG 预处理可通过激活 AMPK 信号通路显著改善心脏功能并抑制 ERS，同时可改善心脏功能、减轻心肌损伤、增加细胞活力和减少细胞凋亡。
综上所述，APG 通过激活 AMPK 信号通路和缓解内质网应激来改善 MI/R 损伤。APG 可能是一种具有药理预处理活性的天然产物，这可能有助于我们在未来开发更多针对 MI/R 损伤的新型治疗方法。
