Development of gelatine-covered silica nanoparticles for delivering recombinant human secretory leukocyte protease inhibitor (rhslpi) for reducing myocardial ischaemia/reperfusion injury

Abstract

Ischaemic Heart Disease (IHD) is the main global cause of death. Previous studies indicated that recombinant human secretory leukocyte protease inhibitor (rhSLPI) exhibits a cardioprotective effect against myocardial ischaemia/reperfusion (I/R) injury. However, SLPI has a short half-life in vivo due to digestion by protease enzymes in circulation. Application of nanoparticle encapsulation could be benefit for SLPI delivery. Several types of nanoparticles have been developed to encapsulate SLPI and applied in some disease models. However, silica nanoparticles for rhSLPI delivery, particularly on myocardial I/R injury, has never been studied. In this study, rhSLPI was encapsulated into gelatine-covered silica nanoparticles (GSNPs), which will be further used to determine an in vitro cardioprotective effect against simulated ischaemia/reperfusion injury (sI/R) in rat cardiac myoblast cell line (H9c2). Silica dioxide nanoparticles (SNPs) were fabricated followed by incubation with 0.33 mg/mL of rhSLPI. Finally, SNPs containing rhSLPI were coated with gelatine (GSNPs). The GSNPs and rhSLPI-GSNPs were characterized by particle size, zeta potential, and morphology scanning electron microscope (SEM). The concentration of rhSLPI in rhSLPI-GSNPs and drug release were determined by Enzyme-linked immunosorbent assay (ELISA). Then, cytotoxicity was determined by incubation of GSNPs or rhSLPI-GSNPs with rat cardiac myoblast cell line (H9c2). The results showed that the particle size of SNPs, GSNPs, and rhSLPI-GSNPs were 273, 300, and 301 nm, respectively, with zeta potential of -57.21, -22.40, and -24.50 mV, respectively. One milligram of rhSLPI-GSNPs contained 235 ng of rhSLPI. The cytotoxicity showed no significant difference between cardiac cells. The rhSLPI-GSNPs provided cardioprotective effect to reduce cardiac cell injury and death against sI/R. In conclusion, this is the first study of rhSLPI encapsulated gelatine-covered nanoparticles (rhSLPI-GSNPs) synthesis. rhSLPI -GSNPs provides cardioprotective effect to against an in vitro sI/R in cardiac cells.