ObjectiveTo prepare recombinant human basic fibroblast growth factor (rhbFGF) loaded magnesium-poly(D,L-lactide-co-glycolide) (Mg-PLGA) stent and to evaluate its angiogenesis effect in rat model of hindlimb ischemia.MethodsThe stent was prepared with spiral magnesium (Mg) and loaded with therapeutic agent rhbFGF and PLGA matrix.In vitro drug release study was carried out and the effect was evaluated using a standard animal model of rat hindlimb ischemia.A mechanical drill was conducted and the stent was implanted.The concentrations of Mg2+ in the muscle adjacent to the stent,rat plasma,urine and stools of the experimental animals were tested to analyze the degradation and metabolism of metal Mg.Immunohistochemical staining was performed to evaluate the angiogenesis effect of the stent.ResultsThe drug loaded in the stent could release continuously for about 4 weeks.The concentrations of Mg2+ in the rat plasma,urine and stools were within normal range.Immunohistochemical and quantitative analysis showed that the effect of Mg-PLGA-rhbFGF stent on angiogenesis of rat limb ischemia was better than that of the control group.ConclusionRhbFGF loaded MgPLGA stent could promote angiogenesis of rat limb ischemia,and it may provide theoretical basis for the critical patients suffered from lower limb ischemic disease.

Objective To prepare a novel brain active-targeting endomorphin (EM) loaded hyperbranched polyglycerols-poly (lactic-co-glycolic acid) (HBPG-PLGA) nanoparticles (NPs) and study its mechanism of passing across blood brain barrier (BBB) in brain microvascular endothelial cells (BMEC).Methods The OX26 (transferring receptor monoclonal antibody) conjugated EM loaded HBPG-PLGA NPs was constructed according to water-in-oil-in-water emulation solvent evaporation technique as a novel biodegradable brain active-targeting drug delivery system.The properties of the NPs were evaluated by transmission electron microscope (TEM) in vitro.Through flow cytometry and laser scanning confocal microscope,the mechanism of passing across BBB was evaluated.Results The preparation methodology of NPs was optimized and established.The mean diameter was (170±20) nm and Zeta potential was about-27 mV.Core-shell construction was showed on TEM.Cellular uptake study showed that the uptake of NPs was via a caveolae-mediated endocytic pathway,then endomorphin and carrier were divided into two parts in BMEC.Conclusions The OX26 conjugated EM loaded NPs were stable,and demonstrate remarkable effects on crossing BBB.Cellular uptake by BMEC is a very important mechanism of the NPs' brain activating-targeting effect.

Objective To study the cytotoxicity against brain microvessel endothelial cells and blood compatibility in rats of OX26 conjugated endomorphin (EM) loaded hyperbranched polyglycerols-poly(lactic-co-glycolic acid)(HBPG-PLGA) nanoparticles.Methods Prepared nanoparticles were divided into group B (HBPG-PLGA nanoparticles),group EP (EM-HBPG-PLGA nanoparticles) and group OEP (OX26-EM-HBPG-PLGA nanoparticles).The cytotoxicity against brain microvessel endothelial cells (BMECs) of nanoparticles of different groups were measured by MTT test,haemolysis test,normal haemotological parameter and several primary items of coagulation system were tested after nanoparticles of different groups and different dosages injection on rats.Results ①All the three groups of nanoparticles induced decreased cell viability in a dose dependent manner in MTT test,whereas all groups of nanoparticles showed low cytotoxicity against the BMECs during 30 to 600 μg/ml.②There was no significant difference in haemolysis ratio (P＞0.05) and normal haemotological parameter (P＞0.05).③There was no significant difference between the low dosage of all the three groups of nanoparticles and the control group on the function of coagulation system in rats (P＞0.05).④Compared with C group,high dose groups demonstrated longer prothrombin time (PT),activeated partial thromboplasting time (APTT) and lower fibrinogen (Fbg) (P＜0.05).At the same time,compared with the low dose subgroups,PT and APTT were prolonged,Fbg significantly decreased in the high dose subgroups (P＜0.05 or P＜0.01).Conclusion OX26 coupled with EM-HBPG-PLGA nanoparticles showed low cytotoxicity against BMECs and had no significant effect on the coagulation system in rats with low concentration and low dosage.