The Effect Of Targeted Nanoparticles Embedded With Sildenafil On The Vascular Remodeling In Rats With Pulmonary Arterial Hypertension

Objective:To explore the possible efficacy of glucose modified nanoparticles embedded with sildenafil on amelioration of pulmonary vascular remodeling and right ventricular myocardial hypertrophy,lung tissue phosphorylation of extracellular protein kinase and hexokinase-2 expression and the influence of the mortality in rats treated with monocrotaline.Methods:Part one:Forty-two male Sprague-Dawley rats were randomly divided into 6 groups with 7 rats for each group.All rats,except in Control group,were subjected to 60 mg/kg monocrotaline subcutaneous injection.After 4 weeks MCT insult,the rats received intravenous injection of sildenafil(8 mg/kg)in SIL group,glucose modified nanoparticles(GL group),conventional nanoparticles embedded with sildenafil(L-SIL group,containing sildenafil 8 mg/kg),glucose modified nanoparticles embedded with sildenafil(GL-SIL group,containing sildenafil 8 mg/kg)every other day for 2 weeks.The same volume of normal saline was substituted for drug in Control,MCT group.At the endpoint of experiment,the rats were tracheal intubated and hemodynamic parameters of the rats were measured.The right lower lobes of the lungs were fixed in neutral formaldehyde for morphometric analysis and assessment of the medial thickness of pulmonary arterioles wall.The expressions of?-smooth muscle actin(?-SMA)were detected with immunohistochemistry assay.The cardiomyocyte cell area of right ventricle was also measured under the high-resolution microscope.And other lungs were used to detect phosphorylated extracellular regulatory protein kinase(p-ERK1/2),extracellular regulatory protein kinase(ERK1/2)and hexokinase-2(HK-2)by western blot.Part two:Thirty-six SD male rats were randomly divided into 6 groups:CON group,MCT group,GL group,SIL group,L-SIL group,GL-SIL group.In addition to the CON group,other groups were subjected to 60 mg/kg monocrotaline subcutaneous injection,the treatment group respectively after 4 weeks MCT insult,the rats received intravenous injection of sildenafil(8 mg/kg)in SIL group,glucose modified nanoparticles(GL group),conventional nanoparticles embedded with sildenafil(L-SIL group),glucose modified nanoparticles embedded with sildenafil(GL-SIL group)every day for 2 weeks.the CON group and MCT group were given same volume of normal saline.The time and amount of death of each group were recorded from the day of intervention to 120 days.Part three:Twelve male Sprague-Dawley rats were randomly divided into2 groups with 6 rats for each group were subjected to 60 mg/kg monocrotaline subcutaneous injection.After 4 weeks,the rats received intravenous injection of IR-783 respectively labeled conventional nanoparticles embedded with sildenafil 8 mg/kg(L-SIL group),glucose modified nanoparticles embedded with sildenafil 8 mg/kg(GL-SIL group).4 h after intravenous injection,animals were sacrificed and extracted the heart,liver,spleen,lung,kidney,use Caliper IVIS bioluminescent fluorescence Spectrum type small animal in vivo fluorescence imaging of DiR-loaded nanoparticles and calculate average fluorescent radiation in the lung tissue.Results:Part one:MCT caused marked increase in mean pulmonary arterial pressure(mPAP)and approximated 34 mmHg at D42,the treatment with glucose modified nanoparticles embedded sildenafil significantly inhibited the increase of mPAP after 2 weeks intervention compared with MCT group(25.29±3.35 mmHg versus 34.14±2.27 mmHg,P<0.05).In contrast,the intervention with sildenafil,glucose modified nanoparticles,or nanoparticles embedded sildenafil elicited no beneficial effect on attenuation of mPAP.The increased percentage of medial thickening in pulmonary arterioles and cardio-myocyte volume of right ventricle induced by MCT were markedly suppressed in GL-SIL group(P<0.05).The expression of ?-SMA in the media of pulmonary arterioles wall was unregulated exposure to MCT at D42.The treatment with glucose modified nanoparticles embedded sildenafil significantly inhibited the expression of ?-SMA relative to SIL,GL,L-SIL treatment(P<0.05).Western blot showed that compared with the CON group,the p-ERK1/2 ERK1/2 of MCT group and the expression of HK-2 were increased,while the GL-SIL group significantly reduced the expression of both in the pulmonary arterial hypertension rat model(P<0.05).Part two:All the rats in CON group and GL-SIL group survived;Four rats dead in MCT group and GL group.One rat dead in SIL group and L-SIL group respectively.The death rate of pulmonary hypertension rats could be improved by the injection of glucose modified nanoparticles embedded sildenafil(P<0.05).Part three:The intensity of fluorescent of lung tissue was higher in DiR-loaded glucose modified nanoparticles relative to conventional nanoparticles after 4 h injection.Conclusion:The treatment with glucose modified nanoparticles embedded sildenafil can effectively inhibit the increase in mPAP,percentage of medial thickening,cardiomyocyte hypertrophy of right ventricle,reduce the expression of ?-SMA,p-ERK1/2/ERK1/2,HK-2 and decrease mortality by MCT in rats,which might be associated with high affinity to lung of targeted nanoparticles and high efficiency drug-delivery system.