Effects of glucagon-like peptide 1 analogs in combination with insulin on myocardial infarct size in rats with type 2 diabetes mellitus

AIM To evaluate the effects of glucagon-like peptide-1 analogs(GLP-1 a) combined with insulin on myocardial ischemiareperfusion injury in diabetic rats.METHODS Type 2 diabetes mellitus(T2 DM) was induced in maleWistar rats with streptozotocin(65 mg/kg) and verified using an oral glucose tolerance test. After anesthesia, the left coronary artery was occluded for 40 min followed by 80 min reperfusion. Blood glucose level was measured during surgery. Rats were randomized into six groups as follows:(1) control rats;(2) insulin(0.1 U/kg) treated rats prior to ischemia;(3) insulin(0.1 U/kg) treated rats at reperfusion;(4) GLP-1 a(140 mg/kg) treated rats prior to ischemia;(5) GLP-1 a(140 mg/kg) treated rats at reperfusion; and(6) rats treated with GLP-1 a(140 mg/kg) prior to ischemia plus insulin(0.1 U/kg) at reperfusion. Myocardial area at risk and infarct size was measured planimetrically using Evans blue and triphenyltetrazolium chloride staining, respectively.RESULTS There was no significant difference in the myocardial area at risk among groups. Insulin treatment before ischemia resulted in a significant increase in infarct size(34.7% ± 3.4% vs 18.6% ± 3.1% in the control rats, P < 0.05). Post-ischemic administration of insulin or GLP-1 a had no effect on infarct size. However, pre-ischemic administration of GLP-1 a reduced infarct size to 12% ± 2.2%(P < 0.05). The maximal infarct size reduction was observed in the group treated with GLP-1 a prior to ischemia and insulin at reperfusion(8% ± 1.6%, P < 0.05 vs the control and GLP-1 a alone treated groups).CONCLUSION GLP-1 a pre-administration results in myocardial infarct size reduction in rats with T2 DM. These effects are maximal in rats treated with GLP-1 a pre-ischemia plus insulin at reperfusion.

Quantitative Mitochondrial Proteomics Study on Protective Mechanism of Grape Seed Proanthocyanidin Extracts Against Ischemia/Reperfusion Heart Injury in Rat

Cardiac ischemia/reperfusion（I/R） injury is a critical condition,often associated with high morbidity and mortality.The cardioprotective effect of grape seed proanthocyanidin extracts（GSPE） against oxidant injury during I/R has been described in previous studies.However,the underlying molecular mechanisms have not been fully elucidated.This study investigated the effect of GSPE on reperfusion arrhythmias especially ventricular tachycardia（VT） and ventricular fibrillation（VF）,the lactic acid accumulation and the ultrastructure of ischemic cardiomyocytes as well as the global changes of mitochondria proteins in in vivo rat heart model against I/R injury.GSPE significantly reduced the incidence of VF and VT,lessened the lactic acid accumulation and attenuated the ultrastructure damage.Twenty differential proteins related to cardiac protection were revealed by isobaric tag for relative and absolute quantitation（iTRAQ） profiling.These proteins were mainly involved in energy metabolism.Besides,monoamine oxidase A（MAOA） was also identified.The differential expression of several proteins was validated by Western blot.Our study offered important information on the mechanism of GSPE treatment in ischemic heart disease.

组织自发荧光在大鼠心肌缺血实验中的应用

目的基于特定的荧光检测技术,探讨组织自发荧光在大鼠心肌缺血性损伤实验中的应用。方法本研究通过Kodak FX Pro活体成像技术检测大鼠心肌组织的自发荧光。通过荧光检测,比较正常大鼠和心肌缺血性损伤大鼠的心肌组织对应部位自发荧光的变化,并进行定量分析。结果心肌缺血损伤后,损伤部位组织自发荧光信号明显增强,将荧光信号通过活体成像系统进行定量,与正常心肌组织比较差异有统计学意义。结论大鼠心肌组织在心肌缺血损伤后,心肌组织的自发荧光明显增强,为大鼠心肌缺血损伤模型的研究及其评价提供新的方法。有利于定位、定性、定量比较研究,可用于病理、生理、药理及作用机制等多方面研究。

牡荆素对大鼠在体心肌缺血再灌注损伤的保护作用和部分机制

目的：探讨牡荆素对大鼠在体心肌缺血再灌注损伤的保护作用，并对其部分作用机制。方法建立大鼠在体心肌缺血再灌注损伤动物模型，将其分为模型组、假手术组、葛根素组和牡荆素组，对各组大鼠模型的心肌梗死面积和相关血清标志物进行测定，并对结果进行分析对比。结果药物组大鼠心肌梗死面积均存在不同程度的降低，其中以牡荆素1．5 mg／kg组大鼠IS／AAR下降幅度最大，抑制率为28．71％。结论牡荆素能够有效降低大鼠在体心肌缺血再灌注损伤模型的心肌梗死面积，通过增强机体的抗氧化作用发挥其保护作用。