Modulation Of Macrophages By Targeted Nanoparticles Improves Cardiac Dysfunction In Sepsis

Objective:Preparation of cardiac specific polypeptide（PCM）-modified mesoporous silica nanoparticles（MSN）and L-arginine（LA）-loaded cardiac targeted nanoparticles（PCM-MSN@LA）.To explore the role of PCM-MSN@LA in improving lipopolysaccharide（LPS）-induced septic cardiac insufficiency by regulating macrophages,and to provide an experimental basis for clinical treatment of septic cardiac insufficiency.Methods:1.PCM-MSN@LA was prepared by condensation reaction,and its zeta potential,particle size,targeting and biosafety were tested,and the LA release was determined by dialysis bag method and fluorescence microscope;2.Eighty healthy male C57BL/6j mice were haphazard split into five groups:control group,LPS group,LPS+PCM-MSN group,LPS+PCM-MSN@LA group and LPS+PCM-MSN@LA+low intensity Focused ultrasound（LIFU）group,16 rats in each group.The model was erected by intraperitoneal injection of 40 mg/kg LPS into mice,LPS+PCM-MSN group,LPS+PCM-MSN@LA group and LPS+PCM-MSN@LA+LIFU group were got a shot with 0.5 mg/Kg of PCM-MSN or PCM-MSN@LA via tail vein presently after LPS injection.LPS+PCM-MSN@LA+LIFU group was treated with low-intensity focused ultrasound（LIFU）immediately after tail vein injection.Eight mice in each group were used to perceive the survival rate after drug treatment,and the other eight mice were used to perceive the cardiac function by echocardiography after 12 hours processing.HE staining and F4/80 staining were used to behold myocardial histopathological changes and the positive expression rate of macrophages in myocardial tissue,individually;3.Bone marrow-derived macrophages were randomly split into four groups:Control group,LPS group,LPS+PCM-MSN@LA group and LPS+PCM-MSN@LA+LIFU group.All LPS-containing groups were treated with 5μg/m L LPS.Cells were treated for 16 hours;LPS+PCM-MSN@LA group and LPS+PCM-MSN@LA+LIFU group were disposed of 25μg/m L PCM-MSN@LA presently after LPS healing.In addition,LPS+PCM-MSN The@LA+LIFU group was treated with LIFU immediately after the intervention.Then,the migration of cells in each group was ascertained by Transwell chamber;the m RNA expressions of chemokine ligand 1（CXCL1）,monocyte chemokine-1（MCP-1）,nicotinamide adenine dinucleotide phosphate oxidase（NOX）subunit p22^phoxand p47^phoxwere gauged by real-time fluorescence quantitative polymerase chain reaction（RT q PCR）;the production levels of reactive oxygen species（ROS）,oxidized coenzyme II/reduced coenzyme II（NADP?/NADPH）in each group were determined The ratio,superoxide dismutase（SOD）activity level,mitochondrial ROS production level,and protein expression levels of nuclear factor E2-related factor 1（Nrf1）and nuclear factor E2-related factor 2（Nrf2）were detected by Western blotting（WB）.Results:1.PCM-MSN@LA is spherical,with a particle size of about 226 nm and a Zeta potential of about-19 m V.It has good targeting and biological safety,and can gradually release nitric oxide（NO）with time.2.The survival rate of the LPS group after 24 hours of healing was drastically lower than that of the LPS+PCM@LA group and the LPS+PCM-MSN@LA+LIFU group;echocardiography in the LPS group showed that EF and FS were drastically dwindled and changed,and HE staining indicated that Myocardial tissue was edematous and necrotic,disordered.F4/80 staining showed that the positive rate of macrophages in myocardial tissue was significantly increased（all P<0.05）.Contrasted with LPS group,LPS+PCM-MSN@Both LA group and LPS+PCM-MSN@LA+LIFU group showed multiplied EF and FS,increased myocardial edema,relatively orderly arrangement,and dwindled positive expression rate of macrophages in myocardial tissue.（both P<0.05）,and contrasted with the LPS+PCM-MSN@LA group,the LPS+PCM-MSN@LA+LIFU group had statistically momentous divergences in each quota between the two groups（P<0.05）.However,there was no statistically momentous divergences between the LPS+PCM-MSN group and the LPS group for each quota.3.After LPS-stimulated cells,macrophage migration increased,CXCL1,MCP-1,p22^phoxand p47^phoxm RNA expressions increased,NADP⁺/NADPH ratio increased,SOD activity dwindled,macrophage ROS and mitochondrial ROS production increased,and Nrf1 and Nrf2protein expressions dwindled（all P<0.05）;contrasted with the LPS group,the two groups added with PCM-MSN@LA showed that the migration ability was inhibited,and the m RNA expressions of chemokines CXCL1,MCP-1,and p22^phoxand p47^phoxwere all dwindled,NADP⁺/NADPH ratio decreased,SOD activity increased,macrophage ROS and mitochondrial ROS generation dwindled,Nrf1,Nrf2 protein expression increased（all P<0.05）,and contrasted with the LPS+PCM-MSN@LA group,the LPS+PCM-MSN@LA+LIFU group had statistically momentous divergences in each quota between the two groups（all P<0.05）.Conclusions:In this study,PCM-MSN@LA was successfully prepared,confirming that PCM-MSN@LA improves septic cardiac function by reducing the migration of macrophages to the myocardium,enhancing the antioxidant and reducing effect of macrophages,and reducing the production of ROS in macrophages.