Rg1-Loaded Tetrahedral DNA Nanostructures Attenuate Myocardial Ischemia-Reperfusion Injury by Suppressing Oxidative and Endoplasmic Reticulum Stress.

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) remains a major clinical challenge in the management of acute myocardial infarction. Ginsenoside Rg1, a bioactive component from Panax ginseng, exhibits cardioprotective properties but suffers from poor bioavailability and limited tissue targeting.

METHODS

We designed a novel DNA nanocarrier, Rg1@pTDN, by loading Rg1 onto a tetrahedral DNA nanostructure (TDN) modified with the myocardial-targeting peptide CREKA. The physicochemical characteristics of Rg1@pTDN were evaluated by DLS, zeta potential analysis, AFM, and gel electrophoresis. Biodistribution, biosafety, and cellular uptake were assessed in vitro and in vivo. Cardioprotective efficacy was evaluated in a murine MIRI model and a H/R injury cell model. Mechanistic studies focused on oxidative stress and endoplasmic reticulum (ER) stress pathways.

RESULTS

Rg1@pTDN exhibited uniform nanoscale structure, high Rg1 loading efficiency, and good colloidal stability. In vivo imaging revealed preferential accumulation in cardiac tissue following intravenous administration. Rg1@pTDN was well tolerated and improved survival, cardiac function, and myocardial histology in MIRI mice. It significantly reduced serum CK-MB concentrations and oxidative stress markers (MDA), while increasing antioxidant enzyme activities (SOD, GSH-Px). In vitro, Rg1@pTDN suppressed ROS accumulation and H/R-induced apoptosis in H9c2 cells. Furthermore, Rg1@pTDN alleviated H/R-induced ER stress, as shown by decreased GRP78 and CHOP mRNA expression and reduced phosphorylated PERK and CHOP protein levels.

CONCLUSION

Rg1@pTDN represents a promising nanotherapeutic strategy for myocardial ischemia-reperfusion injury through targeted delivery and dual inhibition of oxidative and ER stress. This DNA-based platform offers a versatile approach for enhancing the efficacy of natural compounds in cardiovascular disease.