人参皂苷Rg1纳米粒局部注射治疗大鼠心肌梗死

Local injection of ginsenoside Rg1 nanoparticles in the treatment of myocardial infarction in rats

背景:人参皂苷Rg1可以减轻心肌梗死小鼠的心肌细胞凋亡与炎症反应,改善小鼠心功能,但以往研究多是腹腔注射给药,将人参皂苷Rg1包裹于纳米粒中应用于心肌梗死的相关研究较少。目的:将人参皂苷Rg1包裹于纳米粒,观察其局部注射治疗大鼠心肌梗死的效果。方法:采用双乳液法制备人参皂苷Rg1纳米粒,检测纳米粒的粒径、形态及电位、包封率与载药量以及体外药物缓释作用。选取64只雄性SD大鼠,利用随机数字表将大鼠分成4组,每组16只:假手术组仅开胸,不结扎冠状动脉左前降支;模型组结扎冠状动脉左前降支复制心肌梗死模型;药物组复制心肌梗死模型后,梗死周围区注射人参皂苷Rg1溶液;纳米粒组复制心肌梗死模型后,梗死周围区注射人参皂苷Rg1纳米粒混悬液。造模28 d后分别进行超声心动图、心肌组织学及RT-qPCR检测。结果与结论:①人参皂苷Rg1纳米粒的平均粒径为(231.28±3.66)nm,Zeta电位(-24.31±3.65)mV,透射电镜下可见该纳米粒呈圆球形,粒径在198 nm左右,纳米粒分散均匀,无团聚,纳米粒的包封率为(69.82±3.21)%,载药量为(6.05±0.02)%,该纳米粒可持续释放人参皂苷Rg1达30 d以上;②超声心动图检测显示,与假手术组相比,模型组左心室功能与结构异常;与模型组比较,药物组、纳米粒组左心室功能与结构均有明显改善,其中以纳米粒组改善更明显;③苏木精-伊红与Masson染色显示,模型组大鼠心肌组织纤维排列松散且不规则,间质水肿并伴有明显充血与炎性细胞浸润,缺血中心及周围可见大量胶原沉积;药物组、纳米粒组大鼠心肌组织纤维排列略松散,排列较模型组规则,间质较少见水肿与炎性细胞浸润,缺血中心及周围胶原沉积明显减少,其中以纳米粒组病理改善更明显;④RT-qPCR检测显示,与模型组比较,药物组、纳米粒组梗死区低氧诱导因子1α、血管性血友病因子、血管内皮生长因子A、血管生成素1、缝隙连接蛋白43、钙黏蛋白的mRNA表达量升高(P<0.05),肿瘤坏死因子α、白细胞介素1β、干扰素γ的mRNA表达量降低(P<0.05),其中以纳米粒组改善更明显;⑤人参皂苷Rg1纳米粒局部给药可抑制梗死心肌组织的炎症反应及心室重塑,改善心功能,促进心肌组织的修复,该作用可能通过提升成血管相关基因与心肌功能蛋白的表达、抑制炎症因子的基因表达有关。

BACKGROUND:Ginsenoside Rg1 can reduce myocardial cell apoptosis and inflammatory response in mice with myocardial infarction,and improve cardiac function in mice.However,most previous studies used intraperitoneal injection.There are few related studies on the application of ginsenoside Rg1 in nanoparticles for myocardial infarction.OBJECTIVE:Ginsenoside Rg1 was coated with nanoparticles to observe the effect of local application on myocardial infarction in rats.METHODS:Ginsenoside Rg1 nanoparticles were prepared by double emulsion method.The particle size,morphology,potential,sealing rate and drug loading of the nanoparticles,as well as the sustained drug release effect in vitro were detected.Sixty-four male Sprague-Dawley rats were randomly divided into four groups(n=16).In sham operation group,only laparotomy was performed without ligation of the left anterior descending coronary artery.In the model group,ligation of left anterior descending coronary artery was conducted to make myocardial infarction model.In the medicine group,after myocardial infarction model was established,ginsenoside Rg1 was intraperitoneally injected.In the nanoparticle group,ginsenoside Rg1 nanoparticle suspension was injected into the peri-infarct area after replicating the myocardial infarction model.Echocardiogram,myocardial histology and RT-qPCR were conducted 28 days after operation.RESULTS AND CONCLUSION:(1)The average particle size of the ginsenoside Rg1 nanoparticles was(231.28±3.66)nm and the Zeta potential was(-24.31±3.65)mV.Transmission electron microscopy showed that the nanoparticles were spherical with a particle size of about 198 nm.The nanoparticles were evenly dispersed without agglomeration and the encapsulation efficiency of the nanoparticles was(69.82±3.21)%.The drug load was(6.05±0.02)%.The nanoparticles could release ginsenoside Rg1 for more than 30 days.(2)Echocardiogram demonstrated that compared with the sham operation group,the left ventricular function and structure of the model group were abnormal.Compared with the model group,the left ventricular function and structure were significantly improved in the medicine group and nanoparticle group;the improvement was more obvious in the nanoparticle group.(3)Hematoxylin-eosin staining and Masson staining showed that the myocardial tissue fibers of the rats in the model group were loosely arranged and irregular;the interstitial edema was accompanied by obvious congestion and inflammatory cell infiltration,and a large amount of collagen deposition was seen in and around the ischemic center.The fibers of the myocardial tissue of the rats in the medicine and nanoparticle groups were slightly loose,and the arrangement was more regular than that in the model group.The interstitial edema and inflammatory cell infiltration were less common,and the collagen deposition in and around the ischemic center was significantly reduced.Among them,the pathological improvement in the nanoparticle group was more obvious.(4)RT-qPCR detection exhibited that compared with the model group,the mRNA expression of hypoxia-inducible factor 1α,von Willebrand factor,vascular endothelial growth factor A,angiopoietin 1,connexin 43,and cadherin increased in the medicine group and nanoparticle group(P<0.05),and the mRNA expression of tumor necrosis factorα,interleukin-1β,and interferonγdecreased(P<0.05),and the improvement was more obvious in the nanoparticle group.(5)Local administration of ginsenoside Rg1nanoparticles can inhibit the inflammatory response and ventricular remodeling of infarcted myocardial tissue,improve cardiac function,and promote the repair of myocardial tissue.This effect may be associated with the expression of myocardium functional proteins and genes that inhibit inflammatory factors through the promotion of vascular-related genes.