Аннотация:Dinitrosyl iron complexes (nitric oxide donors) can be used in cardiology for the treatment of cardiovascular diseases and in oncology as antitumor drugs. Therefore, the synthesis of new dinitrosyl iron complexes and the study of the mechanism of their action is a relevant and important task. The effect of dinitrosyl iron complexes (cytoprotector and cytostatic) on the morphology and nuclear structure of cells was studied using confocal fluorescence microscopy. The results showed that when human lung fibroblasts were treated with a low concentration of DNIC#4 (cytoprotector), the cell morphology and nuclear structure remained virtually unchanged, the actin structure consisted of long, well-organized fibers, and the nuclei had a rounded shape. It was found that after treating multiple myeloma cells with DNIC#7 (cytostatic), dramatic changes in cell morphology were observed, actin fibers and cytoplasmic membranes were destroyed, and the nuclei were fragmented. Thus, the results confirm that DNIC#4 exhibits a cytoprotective effect on cells at low concentrations, and DNIC#7 is a cytotoxic compound. Therefore, DNIC#4 has potential for use in cardiology, and DNIC#7 has potential for the treatment of human multiple myeloma.