The Radiobiologic Characterizations of Normal Lung Cells Treated with Cerium Oxide Nanostructures as Radioprotector against X-Rays Used in Radiotherapy

Abstract

Background: Cerium oxide nanoparticles, or nanoceria, as radioprotectors can play an important role in reducing complication of ionizing radiation. The aim of this study was to reduce the mortality of normal lung cells against 6-MV photon beams by using nanoceria; so that through identifying optimal concentration of nanoceria, it could be used in radiation therapy. Methods: Nanoceria suspensions were sterilized with 70% ethyl alcohol. In order to optimize the nanoparticles distribution in aqueous medium, suspension was shaken by vortex for 3 minutes. Then, the sonication was performed for 2 hours using ultrasound sonicator. MRC-5 cells were cultured in Dulbecco's modified eagle medium/F12 (DMEM/F12) medium, and placed in a high-humidity incubator at 37 °C. To determine the non-toxic concentration, the cells were treated with serial concentrations of 5, 10, 30, 50, 70, 90, 110, 150, 200, 250, and 300 µM of nanoceria. Quantitative radio-protection effect of nanoceria was performed in non-toxic concentrations against 6-MV X-ray with doses of 20, 40, 60, 80, and 100 cGy. Findings: The concentration of 70 μM and low concentrations did not have toxicity for MRC-5 cells. The mean cell viability (%) in this concentration of nanoceria was 89.4 ± 2.6 percent. MRC-5 cells at presence of 70 µM anoceria had significant radiation protection against radiation doses of 40, 80, and 100 cGy compared to the control group. Conclusion: Using cerium oxide nanoparticles can increase the precision of treatment, and reduce secondary effects of radiotherapy.

Keywords

• Radiotherapy
• Radiation protection
• Nanoceria
• Radiobiology