The Comet Assay Did Not Reveal a Decrease in DNA Damage to Lymphocytes Caused by X-ray Radiation under the Action of Na–Cu-Chlorophyllin in a Concentration up to 100 µmol/L

The search for effective but nontoxic radioprotective agents remains the main task of radiobiology. According to a number of reports, these may include preparations based on chlorophyll, in particular, chlorophyllin, a water-soluble product of its saponification. Since many researchers assign DNA damage a key role in the development of negative consequences of ionizing radiation, we conducted an experiment on X‑ray irradiation of a suspension of lymphocytes in solutions of sodium–copper chlorophyllin in the concentration range of 5–100 µmol/L. During it, using an alkaline modification of the gel electrophoresis method of individual cells, we found no significant differences in the DNA content in the tail and the tail moment of the DNA comets of irradiated lymphocytes incubated in chlorophyllin, compared with only irradiated cells. We explain this result by the fact that, most likely, chlorophyllin does not pass through the nuclear membrane from the cytoplasm into the nucleus. It is precisely the absence of chlorophyllin in the nucleus that can explain the fact that the degree of DNA damage in the experimental samples did not differ from that in the control.