Liu Ke-Mei, Zhang Hai-Hong, Wang Ya-Nan, Wang Lian-Mei, Chen Hong-Yu, Long Cai-Feng, Zhang Lian-Feng, Zhang Hong-Bing, Yan Hong-Bing
Department of Coronary Artery Disease, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
Department of Physiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
Chin Med J (Engl). 2017 Jun 5;130(11):1333-1341. doi: 10.4103/0366-6999.206353.
Myocardial infarction (MI) is a major disease burden. Wild-type p53-induced phosphatase 1 (Wip1) has been studied extensively in the context of cancer and the regulation of different types of stem cells, but the role of Wip1 in cardiac adaptation to MI is unknown. We investigated the significance of Wip1 in a mouse model of MI.
The study began in June 2014 and was completed in July 2016. We compared Wip1-knockout (Wip1-KO) mice and wild-type (WT) mice to determine changes in cardiac function and survival in response to MI. The heart weight/body weight (HW/BW) ratio and cardiac function were measured before MI. Mouse MI was established by ligating the left anterior descending (LAD) coronary artery under 1.5% isoflurane anesthesia. After MI, survival of the mice was observed for 4 weeks. Cardiac function was examined by echocardiography. The HW/BW ratio was analyzed, and cardiac hypertrophy was measured by wheat germ agglutinin staining. Hematoxylin and eosin (H&E) staining was used to determine the infarct size. Gene expression of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) was assessed by quantitative real-time polymerase chain reaction (qPCR), and the levels of signal transducers and activators of transcription 3 (stat3) and phosphor-stat3 (p-stat3) were also analyzed by Western blotting. Kaplan-Meier survival analysis, log-rank test, unpaired t-test, and one-way analysis of variance (ANOVA) were used for statistical analyses.
Wip1-KO mice had a marginally increased HW/BW ratio and slightly impaired cardiac function before LAD ligation. After MI, Wip1-deficient mice exhibited increased mortality (57.14% vs. 29.17%; n = 24 [WT], n = 35 [Wip1-KO], P< 0.05), increased cardiac hypertrophy (HW/BW ratio: 7 days: 7.25 ± 0.36 vs. 5.84 ± 0.18, n = 10, P< 0.01, and 4 weeks: 6.05 ± 0.17 vs. 5.87 ± 0.24, n = 10, P > 0.05; cross-sectional area: 7 days: 311.80 ± 8.29 vs. 268.90 ± 11.15, n = 6, P< 0.05, and 4 weeks: 308.80 ± 11.26 vs. 317.00 ± 13.55, n = 6, P > 0.05), and reduced cardiac function (ejection fraction: 7 days: 29.37 ± 1.38 vs. 34.72 ± 1.81, P< 0.05, and 4 weeks: 19.06 ± 2.07 vs. 26.37 ± 2.95, P< 0.05; fractional shortening: 7 days: 13.72 ± 0.71 vs. 16.50 ± 0.94, P< 0.05, and 4 weeks: 8.79 ± 1.00 vs. 12.48 ± 1.48, P< 0.05; n = 10 [WT], n = 15 [Wip1-KO]). H&E staining revealed a larger infarct size in Wip1-KO mice than in WT mice (34.79% ± 2.44% vs. 19.55% ± 1.48%, n = 6, P< 0.01). The expression of IL-6 and p-stat3 was downregulated in Wip1-KO mice (IL-6: 1.71 ± 0.27 vs. 4.46 ± 0.79, n = 6, P< 0.01; and p-stat3/stat3: 1.15 ± 0.15 vs. 1.97 ± 0.23, n = 6, P< 0.05).
The results suggest that Wip1 could protect the heart from MI-induced ischemic injury.
心肌梗死（MI）是一种主要的疾病负担。野生型p53诱导磷酸酶1（Wip1）已在癌症及不同类型干细胞的调控背景下得到广泛研究，但Wip1在心脏对心肌梗死的适应性反应中的作用尚不清楚。我们在心肌梗死小鼠模型中研究了Wip1的意义。
研究于2014年6月开始，2016年7月完成。我们比较了Wip1基因敲除（Wip1-KO）小鼠和野生型（WT）小鼠，以确定心肌梗死后心脏功能和生存率的变化。在结扎左冠状动脉前降支（LAD）之前测量心脏重量/体重（HW/BW）比值和心脏功能。在1.5%异氟烷麻醉下通过结扎左冠状动脉前降支建立小鼠心肌梗死模型。心肌梗死后，观察小鼠生存4周。通过超声心动图检查心脏功能。分析HW/BW比值，并通过麦胚凝集素染色测量心肌肥大。苏木精和伊红（H&E）染色用于确定梗死面积。通过定量实时聚合酶链反应（qPCR）评估白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）的基因表达，并通过蛋白质印迹法分析信号转导子和转录激活子3（stat3）及磷酸化stat3（p-stat3）的水平。采用Kaplan-Meier生存分析、对数秩检验、非配对t检验和单因素方差分析（ANOVA）进行统计分析。
在结扎LAD之前，Wip1-KO小鼠的HW/BW比值略有增加，心脏功能略有受损。心肌梗死后，Wip1基因缺陷小鼠的死亡率增加（57.14%对29.17%；n = 24 [WT]，n = 35 [Wip1-KO]，P<0.05），心肌肥大增加（HW/BW比值：7天：7.25±0.36对5.84±0.18，n = 10，P<0.01；4周：6.05±0.17对5.87±0.24，n = 10，P>0.05；横截面积：7天：311.80±8.29对268.90±11.15，n = 6，P<0.05；4周：308.80±11.26对317.00±13.55，n = 6，P>0.05），心脏功能降低（射血分数：7天：29.37±1.38对34.72±1.81，P<0.05；4周：19.06±2.07对26.37±2.95，P<0.05；缩短分数：7天：13.72±0.71对16.50±0.94，P<0.05；4周：8.79±1.00对12.48±1.48，P<0.05；n = 10 [WT]，n = 15 [Wip1-KO]）。H&E染色显示Wip1-KO小鼠的梗死面积大于WT小鼠（34.79%±2.44%对19.55%±1.48%，n = 6，P<0.01）。Wip1-KO小鼠中IL-6和p-stat3的表达下调（IL-6：1.71±0.27对4.46±0.79，n = 6，P<0.01；p-stat3/stat3：1.15±0.15对1.97±0.23，n = 6，P<0.05）。
结果表明，Wip1可保护心脏免受心肌梗死诱导的缺血性损伤。
