Department of Hematology, The Second Hospital, Cheeloo College of Medicine, Shandong University, P.R. China
Institute of Biotherapy for Hematological Malignancies, The Second Hospital, Cheeloo College of Medicine, Shandong University, P.R. China
Curr Pharm Biotechnol. 2020;21(13):1386-1393. doi: 10.2174/1389201021666200605104540.
The aim of this study was to explore the inhibitory effect of baicalin on myocardial apoptosis induced by Ischemia-Reperfusion (I/R).
Sprague Dawley rats' heart and myocardial cells I/R model were established in vivo and vitro, then 100 mg/kg and 10 μmol/l baicalin were administrated, respectively. The experiment was randomly divided into 4 groups (n=10): Control; I/R; IR+DMEM; and I/R+baicalin groups. Postoperation, the Left Ventricular (LV) End-Diastolic Pressure (LVEDP), the maximum velocity of LV contraction (dP/dtmax) and the maximum velocity of LV diastole (dP/dtmin) were recorded by the transthoracic echocardiography; the myocardial apoptosis percentage was analyzed by Annexin VFITC/ PI and TUNEL staining, and the apoptosis gene and protein were detected by RT-PCR and western blot. Furthermore, the protein expression of the calcium-sensing receptor (CaSR) and ERK1/2 phosphorylation were observed by western blot and Fura-2-acetoxymethyl ester. Moreover, primary rats' cardiomyocytes were cultured and ERK1/2 specific inhibitor PD98059 was added to the culture medium. The cell survival rate, vitality and apoptosis were detected by MTT, lactate dehydrogenase (LDH) and TUNEL staining assay Kit, respectively.
Our present study showed that baicalin significantly improved LV hemodynamic parameters and myocardial apoptosis in myocardial I/R injury rats. Furthermore, we found that baicalin could down-regulate the protein expression of CaSR, but up-regulate the protein expression of ERK1/2. Furthermore, when the cells were pretreated with ERK1/2 inhibitor PD98059, the cells survival rate significantly decreased, but LDH activity and apoptosis significantly increased. The results indicated that the effect of baicalin on myocardial I/R injury could be inhibited by ERK1/2 inhibitor.
In conclusion, our data suggests that baicalin attenuates I/R-induced myocardial injury maybe through the suppression of the CaSR/ERK1/2 signaling pathway.
本研究旨在探讨黄芩素对缺血再灌注（I/R）诱导的心肌细胞凋亡的抑制作用。
建立了体内和体外的 Sprague Dawley 大鼠心脏和心肌细胞 I/R 模型，分别给予 100mg/kg 和 10μmol/L 黄芩素。实验随机分为 4 组（n=10）：对照组；I/R 组；I/R+DMEM 组；I/R+黄芩素组。术后通过经胸超声心动图记录左心室（LV）舒张末期压（LVEDP）、LV 收缩最大速度（dP/dtmax）和 LV 舒张最大速度（dP/dtmin）；通过 Annexin VFITC/PI 和 TUNEL 染色分析心肌细胞凋亡率，通过 RT-PCR 和 Western blot 检测凋亡基因和蛋白；进一步通过 Western blot 和 Fura-2-乙酰氧基甲酯观察钙敏感受体（CaSR）和 ERK1/2 磷酸化的蛋白表达；此外，在原代大鼠心肌细胞培养中加入 ERK1/2 特异性抑制剂 PD98059，通过 MTT、乳酸脱氢酶（LDH）和 TUNEL 染色试剂盒检测细胞存活率、活力和凋亡。
本研究表明，黄芩素可显著改善心肌 I/R 损伤大鼠的 LV 血流动力学参数和心肌细胞凋亡。此外，我们发现黄芩素可下调 CaSR 蛋白表达，上调 ERK1/2 蛋白表达。此外，当细胞用 ERK1/2 抑制剂 PD98059 预处理时，细胞存活率显著降低，但 LDH 活性和凋亡显著增加。结果表明，ERK1/2 抑制剂可抑制黄芩素对心肌 I/R 损伤的作用。
总之，本研究数据表明，黄芩素通过抑制 CaSR/ERK1/2 信号通路减轻 I/R 诱导的心肌损伤。
