Formulation and characterization of ginsenoside Rh2-loaded casein nanoparticles for enhanced radioprotection

Ionizing radiation poses a significant threat to human health and necessitates the development of effective radioprotective agents. In this study, the radioprotective efficacy of ginsenoside Rh2-loaded casein nanoparticles (Rh2-CNPs) was synthesized and evaluated. The Rh2-CNPs were prepared using a modified co-precipitation method. Physicochemical characterization revealed nanoparticles with an average hydrodynamic diameter of 180 ± 15 nm, a zeta potential of -28 ± 2 mV, an encapsulation efficiency of 75.3 ± 8.5%, and a loading capacity of 23.4 ± 5.9%, indicating successful drug incorporation and good initial dispersion properties. Scanning electron microscopy confirmed a spherical morphology and smooth surfaces. FTIR analysis showed successful encapsulation by hydrogen bonding. In vitro release studies showed a sustained-release profile with 72% drug release after 24 h. In vivo, 32 male BALB/c mice were divided into four groups: Control (C), Radiation (R), Free Ginsenoside Rh2(FG) and Nano-Ginsenoside Rh2 (NG). Mice in the FG and NG groups received 150 mg Rh2/kg/day and 75 mg Rh2-equivalent/kg/day, respectively, for 21 days prior to 5 Gy whole-body γ-radiation exposure. Biochemical analyses were performed 24 h after irradiation. Radiation significantly induced oxidative stress and inflammation, as reflected by decreased SOD and GSH-Px activities in the spleen, increased MDA levels, increased proinflammatory cytokines in serum (TNF-α, IL-6, IFN-γ) and decreased immunoregulatory cytokines in the spleen (IL-2, IL-10). Pretreatment with ginsenoside, especially with the NG formulation, effectively mitigated these adverse effects. PCA and hierarchical clustering clearly separated the experimental groups. These results suggest that Rh2-CNPs exhibit radioprotective effects in this acute model.