Nanocurcumin as a radioprotective agent against radiation-induced mortality in mice

Curcumin, a natural plant product, is commonly known as wonder drug of life, but the poor bioavailability of its free form has hindered its clinical development. The aim of the present study was to investigate the radioprotective effect of nanocurcumin on survival of mice under whole body X-ray irradiation. The Naval Medical Research Institute (NMRI) mice randomly assigned to separate groups and received nanocurcumin via oral gavage at different time points related to irradiation. The survival of mice was evaluated daily for 30 days post-irradiation and finally, the LD50/30 was calculated using Probit analysis. The 30-day survival curve was plotted using the Kaplan-Meier survival curve and the median survival of different subgroups was compared using log-rank test. The P-values less than 0.05 were considered significant. Our results showed that the administration of oral nanocurcumin could effectively reduce the mortality rate in the irradiated mice. Five days pretreatment with nanocurcumin (4 mg/kg/day) induced maximum radioprotective effect. The LD50/30 was 7.18 Gray (Gy) (95% confidence interval [CI]: 6.59-7.77) and 8.78 Gy (95% CI: 8.14-9.50) for irradiation-only and the optimum nanocurcumin group (pre-irradiation group), respectively (dose reduction factor [DRF] = 1.22). Continued administration of nanocurcumin up to seven days post-irradiation resulted in no further radioprotection. The results obtained in this study confirmed the efficacy of nanocurcumin as a radioprotective agent against radiation-induced mortality in mice. The specific characteristics of nanocurcumin, such as non-toxicity, edibility, availability, make this phytochemical as a potential radioprotective agent in the radiotherapy setting and radiation accidents. Further clinical studies are highly recommended.