RESUMEN
BACKGROUND: To comparatively evaluate the cardioprotective activity of placental growth factor (PGF) delivered through direct injection and a nanoparticle-based system respectively and to study the underlying mechanisms in a rat model of acute myocardial infarction (AMI). METHODS: Poly lactic-co-glycolic acid (PLGA)-based PGF-carrying nanoparticles (PGF-PLGANPs) were created. The mean size and morphology of particles were analyzed with particle size analyzer and transmission electronic microscopy (TEM). Encapsulation efficiency and sustained-release dose curve were analyzed by ELISA. Sprague-Dawley rats were randomized into four groups (n = 10). While animals in the first group were left untreated as controls, those in the other 3 groups underwent surgical induction of AMI, followed by treatment with physiological saline, PGF, and PGF-PLGANPs, respectively. Cardiac function was evaluated by transthoracic echocardiography at 4 weeks after treatment. At 6 weeks, rats were sacrificed, infarction size was analyzed with Masson trichrome staining, and protein contents of TIMP-2, MT1-MMP and MMP-2 at the infarction border were determined by immunohistochemistry and western blotting analysis. RESULTS: PGF was released for at least 15 days, showing successful preparation of PGF-PLGANPs. Coronary artery ligation successfully induced AMI. Compared to physiological saline control, PGF, injected to the myocardium either as a nude molecule or in a form of nanoparticles, significantly reduced infarction size, improved cardiac function, and elevated myocardial expression of TIMP-2, MT1-MMP, and MMP-2 (P < 0.05). The effect of PGF-PLGANPs was more pronounced than that of non-encapsulated PGF (P < 0.05). CONCLUSION: Target PGF delivery to myocardium may improve cardiac function after AMI in rats. PLGA-based nanoparticles appear to be a better approach to delivery PGF. PGF exerts its cardioprotective effect at least partially through regulating metalloproteinase-mediated myocardial tissue remodeling.
Asunto(s)
Cardiotónicos/administración & dosificación , Portadores de Fármacos , Ácido Láctico/química , Infarto del Miocardio/tratamiento farmacológico , Nanopartículas , Ácido Poliglicólico/química , Proteínas Gestacionales/administración & dosificación , Animales , Cardiotónicos/química , Química Farmacéutica , Preparaciones de Acción Retardada , Modelos Animales de Enfermedad , Humanos , Inyecciones Intralesiones , Metaloproteinasa 14 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocardio/metabolismo , Miocardio/patología , Factor de Crecimiento Placentario , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Proteínas Gestacionales/química , Ratas Sprague-Dawley , Proteínas Recombinantes/administración & dosificación , Solubilidad , Volumen Sistólico/efectos de los fármacos , Factores de Tiempo , Inhibidor Tisular de Metaloproteinasa-2/metabolismo , Función Ventricular Izquierda/efectos de los fármacos , Remodelación Ventricular/efectos de los fármacosRESUMEN
OBJECTIVE: To investigate lyophilization of SM-SLN. METHOD: The parameters of lyophilization process was optimized. In addition, the protective effect of various types and concentrations of cryoprotectants were tested by shape, colour and disparity. RESULT: The mixture of 2% lactose and 2% glucose could better prevent nanoparticles from aggregating, the optimal lyophilization process was followed: precooled at -45 degrees C for 10 hr; primary drying at -25 degrees C for 5 hr; secondary drying at 10 degrees C for 3 hr; finally drying at 30 degrees C for 6 hr. CONCLUSION: Changes in particle size distribution during lyophilization could be minimized by optimizing the parameters of the lyophilization process and adding supporting agent.