Development of gelatin-silicon dioxide nanoparticles (GSNPs) encapsulating recombinant human secretory leukocyte protease inhibitor (rhSLPI) for reducing in vitro myocardial ischemia/reperfusion injury

Abstract

Ischemic Heart Disease (IHD) is the main global cause of death. Previous studies indicate that recombinant human secretory leukocyte protease inhibitor (rhSLPI) exhibits a cardioprotection effect against myocardial ischemia and reperfusion (I/R) injury. However, SLPI has a short half-life in vivo due to protease enzymes in circulation. Application of nanoparticle encapsulation could be beneficial for SLPI delivery. Several types of nanoparticles have been used 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 Gelatin-Silica dioxide nanoparticles (GSNPs), which will be further used to determine an in vitro cardioprotective effect against simulated ischemia/reperfusion injury in cardiomyocytes. Silica dioxide nanoparticles (SNPs) were fabricated followed by incubation with 0.33 mg/mL of rhSLPI. Finally, SNPs containing rhSLPI were coated with gelatin (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 was determined by ELISA. Next, cytotoxicity was determined by incubation of GSNPs or rhSLPI-GSNPs with rat cardiac myoblast cell line (H9c2). The results show that SNPs, GSNPs, and rhSLPI-GSNPs are sized 280, 303, and 302 nm, respectively, and have a zeta potential of −27.8, −24.4, and −21.5 mV, respectively. SEM indicated a thin layer of gelatin covering SNPs, and the value of zeta potential of SNPs was changed when they were covered by gelatin, indicating a successful coating process. 20 μL of rhSLPI-GSNPs verified by ELISA showed the concentration of rhSLPI was 50.89 ng/mL. The cytotoxicity showed no significant difference between cardiac cells with or without rhSLPI-GSNPs. In conclusion, the researchers were able to fabricate Gelatin-Silica dioxide nanoparticles (GSNPs) to deliver rhSLPI which was used to study cardiomyocyte subjected to simulated ischemia/reperfusion (sI/R) injury.