RESUMO
Electron microscopic study of Lewis lung carcinoma cell mitochondria after intravenous injection of a magnetosensitive nanocomplex based on ferric oxide (Fe3O4) nanoparticles and doxorubicin followed by radiofrequency hyperthermia showed that a common increase of the electron density of the cytoplasm was paralleled by mitochondrial edema in comparison with organelles of animals receiving doxorubicin alone. These changes were accompanied by virtually total lysis of the cristae and sharp clarification of mitochondrial matrix, which was seen from appreciable increase in mitochondria image brightness. Morphometric analysis showed lesser perimeter, area, and mean radius of the tumor cell mitochondria in animals receiving the injection of magnetosensitive nanocomplex and exposed to radiofrequency hyperthermia in comparison with those injected with doxorubicin alone. Histograms of distribution of the perimeter, area, and mean radius of the mitochondria after combined exposure to the nanocomplex and hyperthermia showed bimodal asymmetrical distribution. Injection of the magnetosensitive nanocomplex followed by radiosensitive hyperthermia led to more significant impairment of the tumor cell mitochondrial ultrastructure than doxorubicin alone.
