Wang Jin, Wang Xue-Jiao, Zhang Yan, Shi Wen-Juan, Lei Zhan-Dong, Jiao Xiang-Ying
Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China.
Department of Foreign Languages, Changzhi Medical College, Changzhi, China.
Cardiovasc Diagn Ther. 2022 Jun;12(3):289-304. doi: 10.21037/cdt-21-732.
Myocardial infarction (MI) is a common cause of death. Thioredoxin-interacting protein (TXNIP) expression increases after MI, and it exerts a negative regulatory effect on cardiac function after MI. Our study aimed to investigate the specific regulatory mechanism of TXNIP on angiogenesis and cardiomyocyte apoptosis after MI.
The gene knock-in (-KI) and knock-out (-KO) mice were generated, respectively. Eight-week-old male -KO, -KI, and wild type (WT) mice were subjected to MI by permanent ligation of the left anterior descending artery. Cardiomyocyte apoptosis was detected by TUNEL assay on the 4th post-surgery day. The expressions of TXNIP, hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), phosphorylated protein kinase B (p-AKT), p-AMP-activated protein kinase (p-AMPK), cleaved caspase-3, and caspase-3 were detected by Western blot. Quantitative real-time PCR was performed to detect the expression of , , , prolyl hydroxylase () 1, and factor inhibiting HIF (). In addition, the superoxide dismutase (SOD) activity and malondialdehyde (MDA) level in each group were also measured. On day 7 after MI, the hearts of sacrificed animals were analyzed by immunohistochemistry to assess CD31 expression and determine the density of angiogenesis. One month after treatment, the cardiac functional and structural changes were determined by echocardiography and the level of myocardial fibrosis was observed by Masson staining.
Compared with WT mice, -KO mice had a significantly improved cardiac functional recovery after MI, and the proportion of myocardial fibrosis area was dramatically reduced, cardiomyocyte apoptosis was decreased, and angiogenesis was significantly increased; -KI mice reversed in these changes. The expression of HIF-1α, p-AKT, and p-AMPK increased after MI in -KO mice, and the mRNA expression of 1 and decreased. -KI mice reversed in these changes.
After MI, TXNIP down-regulated the level of HIF-1α and VEGF, reduced the number of angiogenesis, increased cardiomyocyte apoptosis, and ultimately led to a poor prognosis of ischemic myocardium. TXNIP was a protein with negative effects after MI and was expected to be a target for the prevention and treatment of MI.
心肌梗死（MI）是常见的死亡原因。硫氧还蛋白相互作用蛋白（TXNIP）在MI后表达增加，对MI后的心脏功能发挥负性调节作用。本研究旨在探讨TXNIP对MI后血管生成和心肌细胞凋亡的具体调节机制。
分别构建基因敲入（-KI）和基因敲除（-KO）小鼠。8周龄雄性-KO、-KI和野生型（WT）小鼠通过永久性结扎左前降支诱导MI。术后第4天通过TUNEL法检测心肌细胞凋亡。通过蛋白质免疫印迹法检测TXNIP、缺氧诱导因子-1α（HIF-1α）、血管内皮生长因子（VEGF）、磷酸化蛋白激酶B（p-AKT）、p-AMP激活蛋白激酶（p-AMPK）、裂解的半胱天冬酶-3和半胱天冬酶-3的表达。采用定量实时PCR检测、、、脯氨酰羟化酶（）1和HIF抑制因子（）的表达。此外，还检测了每组的超氧化物歧化酶（SOD）活性和丙二醛（MDA）水平。MI后第7天，对处死动物的心脏进行免疫组织化学分析，评估CD31表达并确定血管生成密度。治疗1个月后，通过超声心动图确定心脏功能和结构变化，并通过Masson染色观察心肌纤维化水平。
与WT小鼠相比，-KO小鼠MI后心脏功能恢复明显改善，心肌纤维化面积比例显著降低，心肌细胞凋亡减少，血管生成显著增加；-KI小鼠这些变化则相反。-KO小鼠MI后HIF-1α、p-AKT和p-AMPK表达增加，1和的mRNA表达降低。-KI小鼠这些变化则相反。
MI后，TXNIP下调HIF-1α和VEGF水平，减少血管生成数量，增加心肌细胞凋亡，最终导致缺血心肌预后不良。TXNIP是MI后具有负性作用的蛋白，有望成为MI防治的靶点。
