The effect of antioxidants on the survival of yeast cells under the action of X-ray irradiation

Objectives: Saccharomyces yeast is one of the most studied species for the study of eukaryotic cells. The effect of ionizing radiation on living organisms is studied in radiobiology, the main task of which is to identify the laws of the biological reaction of the body to radiation. This will help to develop methods for monitoring radiation reactions and means of protection against radiation. There are unresolved problems in radiobiology, one of which is radiosensitivity. To study radiation sensitivity, the yeast strain Saccharomyces cerevisiae T-985 was used, as well as rutin, a biologically active substance, a flavonoid with antioxidant and other beneficial properties.
Methods. The spectrophotometric method is based on the use of the free stable radical 2,2-diphenyl-1-picrylhydrosyl (DPPH). After the end of cultivation, aliquots of the yeast suspension were taken from the flasks and transferred into glass flasks with a volume of 1 mL for subsequent irradiation at the Model- KALAN 4 X-ray unit in the IMSEN-IFC of the D.I. Mendeleev Russian Chemical University at an absorbed dose rate of 3 Gy/s according to the Fricke dosimeter [10, 11]. To detect the effects of ionizing radiation and compare the results with the control sample, optical density measurement and microscopy were used.
Results. Rutin may have a protective effect on yeast cells after X-ray irradiation. It has been shown in studies that rutin can reduce oxidative stress and DNA damage caused by irradiation. This may be due to its ability to neu-tralize free radicals and repair damaged molecules. Comparing the results of 0.05mM rutin and rutin and hydrogen peroxide systems, it can be noted that the active form of oxygen negatively affects the survival rate of yeast cells. ionol has a favorable effect on survival and repair processes in yeast cells. The addition of hydrogen peroxide significantly decreases the survival rate of cells immediately after irradiation, but promotes the reparative pro-cesses. As a result of experiments, addition of Rutin with the concentration of 5·10-4 mol/L potentially increases the number of viable cells capable of colony formation than addition of Rutin with the concentration of 5·10-5 mol/L. CFU of S. cerevisiae species with the addition of rutin at different concentrations decreases many times in relation to the control after 3 days at a dose of 400 Gy and 800 Gy of X-ray irradiation.
Conclusions. - With increasing irradiation dose the concentration of rutin decreases, which suggests that it is consumed. The radiation chemical yield of rutin consumption was determined: G (0-400)=0.04 molecules/100 eV; G(400-2000)=0.10 molecules/100 eV.
- The inhibition effect in the reaction with DPPH of rutin solutions without irradiation and one day after irradi-ation was determined. The numerical values are in the range from 67% to 86%, which is more than 50%, which means that rutin has high antiradical properties after irradiation.
- Percentage of dead cells in suspension when rutin was added is less compared to the percentage of dead cells in suspension without rutin at the same absorbed doses.
- In tubes with the addition of rutin of different concentrations, which received a dose of 800 Gy, a day after ir-radiation, there is a significant decrease in the percentage of dead cells compared to the same data obtained with-out the addition of rutin. This can be interpreted as active repair processes.
- At addition of rutin with concentration 5·10-4 mol/l the percentage of dead cells is less than at addition of rutin with concentration 5·10-5 mol/l.