1.太原市中心医院心内科;2.山西医科大学实验动物中心;3.人类疾病与动物模型山西省重点实验室
太原市科技项目（项目编号：202264）;山西省科技厅中央引导地方科技发展资金项目（项目编号：YDZJSX2022B009）；山西省基础研究计划项目青年科学研究项目（项目编号：202403021212288）
1.Department of Cardiology of Taiyuan Central Hospital;2.Center for Laboratory Animals, Shanxi Medical University;3.Shanxi Key Laboratory of Laboratory Animals and Animal Models of Human Disease
目的 探讨生长分化因子-15(GDF-15) 通过激活一氧化氮(NO)-环磷酸鸟苷(cGMP)-蛋白激酶G(PKG)信号通路对急性心肌梗死(AMI)大鼠侧枝循环及心功能的影响。方法 通过结扎冠状动脉左前降支,构建AMI大鼠模型,造模成功后,随机分成假手术组、模型组、GDF-15组,每组12只,GDF-15组腹腔注射GDF-15重组蛋白,其余2组注射等量生理盐水,每周2次,连续8周。超声心动图检测大鼠心功能；HE染色观察大鼠心肌组织病理损伤；CD31免疫组化染色观察大鼠侧枝循环的情况；qPCR检测血管内皮生长因子(VEGF)mRNA表达；试剂盒检测NO、活性氧(ROS)、cGMP表达水平；Western blot 检测VEGF、eNOS单体、pser1177eNOS单体、eNOS二聚体及PKG蛋白表达。结果 与假手术相比,模型组左室收缩末期内径(LVEDs)、左室舒张末期内径(LVEDd)增加,左室射血分数(LVEF)、短轴缩短率(FS)降低,心肌细胞坏死严重,梗死区血管密度降低,VEGF mRNA水平降低,NO、eNOS二聚体、cGMP 水平及PKG蛋白表达水平降低,ROS、eNOS单体及pser1177eNOS单体的表达水平增高(P＜0.05)；与模型组相比,GDF-15组LVEDs、LVEDd 降低,LVEF、FS升高,心肌细胞坏死得到缓解,梗死区血管密度明显增加,VEGF mRNA水平增高,VEGF、NO、eNOS二聚体、cGMP 水平及PKG蛋白水平增高,ROS、eNOS单体及pser1177eNOS单体的表达水平降低(P＜0.05)。结论 GDF-15可通过抑制eNOS解偶联并激活NO-cGMP-PKG 通路,促进缺血心肌侧枝循环、改善心功能。
Objective to observe the effects of growth differentiation factor-15 (GDF-15) on collateral circulation and cardiac function in rats with acute myocardial infarction (AMI) by activating the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) signaling pathway. Methods The AMI rat model was constructed by ligating the left anterior descending coronary artery. After successful modeling, the rats were randomly divided into sham operation group, model group, and GDF-15 group, with 12 rats in each group. The rats in the GDF-15 group were intraperitoneally injected with recombinant GDF-15 protein, and the other two groups were injected with the same amount of normal saline twice a week for 8 consecutive weeks. Echocardiography was used to detect the cardiac function of rats; HE staining was used to observe the pathological damage of rat myocardial tissue; CD31 immunohistochemical staining was used to observe the collateral circulation in rats; qPCR was used to detect the expression of vascular endothelial growth factor (VEGF) mRNA; kits were used to detect the expression levels of NO, reactive oxygen species (ROS), and cGMP; Western blot was used to detect the expressions of VEGF, eNOS monomer, pser1177eNOS monomer, eNOS dimer, and PKG protein. Results Compared with the sham operation group, the left ventricular end-systolic diameter (LVEDs), left ventricular end-diastolic diameter (LVEDd) increased, the left ventricular ejection fraction (LVEF), and the short-axis shortening rate (FS) decreased in the model group, the myocardial cell necrosis was severe, the vascular density in the infarcted area decreased, the VEGF mRNA level decreased, the levels of NO, eNOS dimer, cGMP, and the expression of PKG protein decreased, and the expression levels of ROS, eNOS monomer, and pser1177eNOS monomer increased (P < 0.05). Compared with the model group, the LVEDs and LVEDd decreased, the LVEF and FS increased, the myocardial cell necrosis was relieved, the vascular density in the infarcted area increased significantly, the VEGF mRNA level increased, the levels of VEGF, NO, eNOS dimer, cGMP, and the expression of PKG protein increased, and the expression levels of ROS, eNOS monomer, and pser1177eNOS monomer decreased in the GDF-15 group (P < 0.05). Conclusion GDF-15 can promote collateral circulation in ischemic myocardium and improve cardiac function by inhibiting eNOS decoupling and activating the NO-cGMP-PKG pathway.
