Radioprotective activity of the liposomal composition of quercetin in acute radiation syndrome (experimental study)

Abstract

Background. The targeted search for new effective radioprotective agents, especially among compounds with antioxidant properties, remains relevant. Among them, quercetin which has a high specific activity against oxidative stress (cited as a «universal antioxidant») deserves attention. The transport liposomal composition of quercetin, which significantly improves its bioavailability and is the basis of the licensed drug «Lipoflavon®» (LF), is known, but the radioprotective properties of this drug have not been studied. The purpose of the work is to position Lipoflavon as a radioprotector for the first time based on the study of radioprotective activity in an acute experiment with total irradiation of rats. Materials and methods. The rat model of acute radiation syndrome (ARS) was carried out by short-term bilateral total body irradiation (TBI) on a CLINAC (6 MeV) linear accelerator at doses of 5.5 and 7.0 Gy. The control rats were sham-irradiated. The test sample of LF was used for the studies. LF (1.5 mg/mL) was administered to rats 30 min before TBI through the tail vein. The control TBI rats were injected with physiological saline. Experimental rats were randomly assigned into groups as follows: group 1 – non-irradiated control (intact animals); group 2 – irradiated control at a dose of 5.5 Gy (TBI5.5); group 3 – irradiation at a dose of 5.5 Gy with administration of LF (LF + TBI5.5); group 4 – irradiated control at a dose of 7.0 Gy (TBI7.0); group 5 – irradiation at a dose of 7.0 Gy with administration of LF (LF + TBI7.0). Clinical characteristics of ARS, overall survival, and the mean survival time of the dead animals were determined. The profiles of lethality («peaks of death») were calculated as total rat lethality (%) in certain time periods of the ARS. In hematological studies, LF was administered 24 h prior to TBI and twice a week the next 4 weeks after TBI. The hematological parameters were monitored on days 3, 7, 14 and 21 after TBI. Results. It was established that prophylactic LF administered 30 min before TBI at doses of 5.5 and 7.0 Gy, which were LD20/30 and DL73.3/30, increased the 30-day survival rate of the irradiated rats to 90 and 40% respectively, compared to 80 and 26.7% in irradiated control, and changed the radiation lethality profile of the rats in the model of ARS. The radioprotective activity of LF manifested in the form of the absence of early and late peaks of death of the irradiated rats and the survival time of more than 30 days after the treatment in 40% of rats with LD73,3/30. Prophylactic and therapeutic administration of LF prevented development of severe leukopenia and thrombocytopenia and contributed to a more rapid and sustained recovery of erythrocytes during the period of ARS. The most efficient radioprotective therapeutic effect of LF was observed in rats with a dose of LD73.3/30. Conclusions. The results of the study substantiate the radioprotective activity of Lipoflavon in ARS and help develop the new approaches to using the licensed drug «Lipoflavon®» as an effective pharmacological therapeutic agent for radiation protection in acute radiation.