Radio-Protective Effects of Selenium Nanoparticles Synthesized Using Aqueous Extract of Rhodiola on Mice Irradiated by 60Co γ-Rays

Aim: Nanobiotechnology has grown rapidly in recent years and constitutes an integral part of modern disease diagnosis and treatment. The goal of this study was to evaluate the protective effect of synthesized selenium nanoparticles (SeNPs) against ionizing radiation (IR)-induced hematopoietic system injury. Methods: An aqueous extract of Rhodiola (RHO) was used for the synthesis of SeNPs (RHO-SeNPs). The resulting nanoparticles were characterized by ultraviolet–visible spectrophotometry and transmission electron microscopy, followed by biological assessment (antioxidant and cytotoxicity). Experiments with BALB/c mice and mouse hematopoietic stem cells (HSCs) exposed to 60Co γ-rays were used to evaluate the therapeutic efficiency of RHO-SeNPs. Immunohistochemistry, ELISA, JC-1 staining, CCK-8, TUNEL, flow cytometry, and Western blot were employed to investigate the underlying mechanisms. Results: RHO-SeNPs showed excellent antioxidant performance and had no toxicity in the major organs of BALB/c mice when administered at ≤20 mg/kg. RHO-SeNPs dose-dependently improved hematopoietic function and survival rate of IR-exposed BALB/c mice, in addition to suppressing mitochondrial oxidative stress, inflammatory responses, and bone marrow cell apoptosis. In vitro studies revealed that RHO-SeNPs limited Kelch-like ECH-associated protein 1 (KEAP1) expression and induced nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), thereby attenuating oxidative stress and HSC apoptosis. Both in vivo and in vitro experiments demonstrated that the disruption of NRF2 nuclear translocation partly abolished the radioprotection of RHO-SeNPs. Conclusion: These findings identify the mechanisms underlying the radioprotection of RHO-SeNPs and their potential role as a medical countermeasure against IR exposure.