葛根素PEG-PLGA纳米胶束的体外评价、细胞摄取及抗急性心肌缺血的研究

In vitro evaluation, cellular uptake and anti-acute myocardial ischemia effect of puerarin PEG-PLGA micelles

PUE@PEG-PLGA纳米胶束具有粒径小,载药量高,释药缓慢等优良特点。TEM电镜结果表明PUE@PEG-PLGA纳米胶束呈核壳状圆球型结构;采用芘测定法测定PEG-PLGA纳米胶束的临界胶束浓度(CMC)大约为4.8 mg·L-1;激光共聚焦试验表明,PEG-PLGA纳米胶束可以增强香豆素-6细胞摄取量,且可聚集在线粒体周围,细胞外药物残留量定量结果也可间接证实,PEG-PLGA纳米胶束可以促进药物的细胞摄取。采用结扎冠状动脉制备急性心肌缺血模型大鼠,再随机分为假手术组,模型组,PUE组和PUE@PEG-PLGA高、中、低剂量组,在结扎后5 min各给药组尾iv给药。监测心电图ST段变化,测定血清肌酸激酶(CK)、乳酸脱氢酶(LDH)、天冬氨酸转氨酶(AST)和丙二醛(MDA)水平,并测量心肌梗死面积。PUE和PUE@PEG-PLGA纳米胶束均能降低升高的ST段,降低血清中CK,LDH,AST,MDA水平,减少心肌梗死面积;其中PUE@PEG-PLGA中、高剂量组的药效明显强于PUE组,低剂量组基本与PUE组等效。PUE@PEG-PLGA纳米胶束很大程度上提高PUE心肌细胞摄取量,增强药物抗急性心肌缺血作用,减少给药剂量。

PUE@PEG-PLGA micelles has excellent characteristics such as small particle size,high drug loading and slow drug release.The results of TEM electron microscopy showed that PUE@PEG-PLGA micelles had obvious core-shell structure.The critical micelle concentration(CMC)of PEG-PLGA micelles determined by pyrene assay was about 4.8 mg·L-1.Laser confocal experiments showed that PEG-PLGA micelles can enhance the cellular uptake of coumarin-6 and aggregate around the mitochondria;quantitative results of extracellular drug residues also indirectly confirmed that PEG-PLGA micelles can promote cellular uptake of the drug.Acute ischemic myocardial model rats were prepared by coronary artery ligation,and then the model rats were randomly divided into six groups:Sham operation group,model group,puerarin(PUE)group,as well as low-,mid-,and high-dose PUE@PEG-PLGA micelles groups.Drugs were given by iv administration 5 min after the ligation.The ST segment changes in the electrocardiogram were monitored;serum creatine kinase(CK),lactate dehydrogenase(LDH),aspartate aminotransferase(AST),and malondialdehyde(MDA)levels were detected and myocardial infarct size was also measured.Both PUE and PUE@PEG-PLGA micelles can reduce the elevated ST segment,reduce serum CK,LDH,AST and MDA levels,and reduce myocardial infarct size.The efficacy of PUE@PEG-PLGA medium and high dose groups was significantly better than that in the PUE group,and the efficacy in PUE@PEG-PLGA low dose group was basically equivalent to that in the PUE group.PUE@PEG-PLGA micelles can greatly improve the cardiomyocytes uptake of PUE,enhance the anti-acute myocardial ischemia effect of drugs,and reduce its dosage.