Cardioprotective effect of isorhamnetin against myocardial ischemia reperfusion (I/R) injury in isolated rat heart through attenuation of apoptosis

In this study, we investigated the effects of isorhamnetin on myocardial ischaemia reperfusion (I/R) injury in Langendorff-perfused rat hearts. Isorhamnetin treatment (5, 10 and 20 μg/mL) significantly alleviated cardiac morphological injury, reduced myocardial infarct size, decreased the levels of marker enzymes (LDH and CK) and improved the haemodynamic parameters, reflected by the elevated levels of the left ventricular developed pressure (LVDP), coronary flow (CF) and the maximum up/down velocity of left ventricular pressure (+dp/dt_max). Moreover, isorhamnetin reperfusion inhibited apoptosis of cardiomyocytes in the rats subjected to cardiac I/R in a dose-dependent manner concomitant with decreased protein expression of Bax and cleaved-caspase-3, as well as increased protein expression of Bcl-2. In addition, I/R-induced oxidative stress was manifestly mitigated by isorhamnetin treatment, as showed by the decreased malondialdehyde (MDA) level and increased antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). These results indicated that isorhamnetin exerts a protective effect against I/R-induced myocardial injury through the attenuation of apoptosis and oxidative stress.     

MT2A对脂多糖介导的人肺毛细血管内皮细胞损伤的保护作用

目的:探索不同浓度的金属硫蛋2A(Metallothionein 2A, MT2A)对脂多糖(Lipopolysaccharid, LPS)介导的人肺微血管内皮细胞损伤的保护作用。方法:培养人肺毛细血管内皮细胞株(Human lung microvascular endothelial cells, HPMVECs),经过一定浓度LPS溶液进行刺激后,利用不同浓度的MT2A与对照组共同培养,一段时间后观察炎性介质IL-6、TNF-α释放的量及荧光显微镜观察组HPMVECs骨架形态变化。结果:各组TNF-α浓度均在0 h最低,随之逐渐升高,到6 h达到高峰;从各时间点来看,除0 h各组TNF-α浓度无显著差异外(F=0.717, P=0.549),其余各时间点B1、B2、B3均显著高于A组(均P0.05)。各组中IL-6浓度均在0 h最低,A组在2 h达到高峰,随后逐渐下降;B1组在4 h达到高峰,随之下降;B2、B3组从0 h开始逐渐升高,到6 h达到峰值;从各时间点来看,除0 h各处理因素无显著差异外(F=2.341, P=0.092),其余各时间点B1、B2、B3均低于A组(均P0.05)。A组6 h小时后纤维状肌动蛋白(F-actin)明显解聚,分布明显减少,应力纤维排列紊乱或者消失;B1组、B2组、B3组6 h小时后,与A组相比,F-actin的分布明显较多,应力纤维排列较为整齐。结论:LPS刺激人肺毛细血管内皮细胞有明显损伤效应,加入MT2A后细胞相关炎性因子释放量、细胞骨架损伤情况明显减轻,表明一定浓度的MT2A对LPS介导的肺毛细血管损伤有明显保护作用。     

心肌带收缩率与急性心肌梗死患者左心室收缩功能关系

目的:急性前壁心肌梗死明显影响室间隔收缩率和左心室射血分数(left ventricular ejection fraction LVEF)。本文旨在探讨心肌带降段及升段收缩率与急性前壁心肌梗死患者LVEF的相关性。方法:收集2015年4月-2017年2月在心内科住院的急性前壁心肌梗死患者36例,正常对照组患者39例。所有患者取左心室长轴M型超声心动图,测量室间隔收缩率、升段收缩率及降段收缩率。心肌梗死左心室射血分数采用双平面Simpson's法计算。结果:与正常对照组相比,心肌梗死组患者舒张末期心肌带升段厚度没有统计学差异(P=0.69),收缩末期升段厚度(P=0.014)更薄、升段收缩率(P0.01)明显降低;心肌梗死组舒张末期降段厚度(P0.01)更薄、收缩末期降段厚度(P0.01)更薄、降段收缩率(P0.01)明显降低;心肌梗死组左心室射血分数与降段收缩率(r~2=0.13,P=0.026)、室间隔增厚率(r~2=0.19,P0.01)呈正相关,与升段收缩率没有相关性(P0.05)。正常对照组左心室射血分数与室间隔增厚率、降段增厚率及升段增厚率无相关性。经过相关分析,筛选出与心肌梗死LVEF的相关因素,进一步经逐步回归分析,得多元线性回归方程为LVEF=48.206+18.914*LVDD(cm)-25.414*LVSD(cm)。结论:急性前壁心肌梗死室间隔降段收缩率明显受损,与左心室射血分数降低有关。多元线性回归方程可估算前壁心肌梗死LVEF。     

静脉溶栓时机对急性ST段抬高型心肌梗死患者溶栓效果及主要不良心脏事件发生率的影响

目的:探讨静脉溶栓时机对急性ST段抬高型心肌梗死患者溶栓效果及主要不良心脏事件发生率的影响。方法:将2016年1月至2017年12月我院接诊的314例急性ST段抬高型心肌梗死患者纳入本研究,按照溶栓治疗时间不同分为A组(发病至溶栓时间6 h)172例、B组(发病至溶栓时间为6～12 h)102例和C组(发病至溶栓时间12 h)40例,比较三组患者溶栓效果、溶栓后ST段回落情况以及住院期间主要不良心脏事件发生情况。结果:A组患者梗死冠脉溶通率、溶栓后ST段回落幅度高于B组和C组,且B组高于C组,差异均有统计学意义(P0.05)。A组患者治疗后ST段回落最大幅度所需时间、住院期间主要不良心脏事件总发生率低于B组和C组,且B组低于C组,差异均有统计学意义(P0.05)。结论:急性ST段抬高型心肌梗死患者发病后6 h内静脉溶栓治疗梗死冠脉溶通率更高、ST段回落效果更好,可降低住院期间主要不良心脏事件发生风险。     

Hyaluronate supports hESC‐cardiomyocyte cell therapy for cardiac regeneration after acute myocardial infarction

IntroductionEnormous progress has been made in cardiac regeneration using human embryonic stem cell‐derived cardiomyocyte (hESC‐CM) grafts in pre‐clinical trials. However, the rate of cell survival has remained very low due to anoikis after transplantation into the heart as single cells. Numerous solutions have been proposed to improve cell survival, and one of these strategies is to co‐transplant biocompatible materials or hydrogels with the hESC‐CMs.MethodsIn our study, we screened various combinations of biomaterials that could promote anoikis resistance and improve hESC‐CM survival upon co‐transplantation and promote cardiac functional recovery. We injected different combinations of Matrigel, alginate and hyaluronate with hESC‐CM suspensions into the myocardium of rat models with myocardial infarction (MI).ResultsOur results showed that the group treated with a combination of hyaluronate and hESC‐CMs had the lowest arrhythmia rates when stimulated with programmed electrical stimulation. While all three combinations of hydrogel‐hESC‐CM treatments improved rat cardiac function compared with the saline control group, the combination with hyaluronate most significantly reduced pathological changes from left ventricular remodelling and improved both left ventricular function and left ventricular ejection fraction by 28 days post‐infarction.ConclusionHence, we concluded that hyaluronate‐hESC‐CM is a superior combination therapy for promoting cardiac regeneration after myocardial infarction.     

海南岛木麻黄林林下植物天然更新影响因素的研究

木麻黄海防林是海南岛重要的海岸生态屏障,天然更新对其持续发挥防护功能具有重要意义。调查发现海南岛大多数木麻黄林林下天然更新困难,然而却存在局部更新良好的现象。为了探究天然更新存在巨大差异的原因,并为促进海南海防林由人工林向近自然林转化提供一定的理论基础,通过分析不同林地更新质量的差异,研究影响木麻黄海防林林下天然更新的主要影响因素。该研究在海南岛木麻黄海防林中共设置73块临时样地,采用方差分析和相关分析等统计方法,分别研究林地所属气候区、林分条件、土壤因子和凋落物累积量对天然更新质量和密度的影响。结果表明:(1)湿润气候区的木麻黄林下更新要显著优于半干旱区;(2)木麻黄林分密度与更新密度和草本盖度存在显著负相关,但林分条件其他因子对更新影响不大;(3)不同更新质量样地的土壤pH和养分均无显著性差异,但铵态氮对幼苗、有机质对幼树的更新存在一定的促进作用;(4)凋落物的累计整体不利于天然更新的进行。结果说明气候因子、木麻黄林分密度、木麻黄凋落物积累量是木麻黄海防林林下植物天然更新的主要影响因素。     

木麻黄种子萌发的限制生态因子

成功的天然更新应同时具备三个条件:(1)种源数量充足、质量良好;(2)适宜种子萌发的微生境;(3)幼苗、幼树存活的生态条件。为进一步揭示海南岛木麻黄(Casuarina equisetifolia)海防林自身无法天然更新的障碍因子,该文对影响其天然更新的三个条件之一的种子萌发条件进行了研究,并探讨了不同的生态因子,如木麻黄化感、土壤酸碱度、盐度、温度、基质类型、水分等对木麻黄种子萌发的影响。结果表明:(1)不同浸提物的不同浸提液浓度处理的种子萌发率与CK组无显著性差异。(2)设定范围内的pH、盐度和温度对木麻黄种子萌发率无显著影响。(3)不同浓度梯度PEG溶液处理的木麻黄种子萌发率存在显著性差异,且伴随PEG溶液浓度增加,木麻黄种子萌发率随之锐减。(4)不同基质及浇水频度对种子萌发率也具有显著影响。从综合PEG干旱胁迫、基质及浇水频度的结果可以发现,木麻黄种子抗旱能力较弱,对水分敏感。因此,水分是制约木麻黄种子萌发的主要限制因子,凋落物层及滨海沙土较差的保水性不同程度地制约了种子的萌发。