Evaluation of Viscosity and Oxidative Stress Induction in Michigan Cancer Foundation-7 Cells Treated with Melatonin Associated with Microemulsion and Polyethylene Glycol 400

Breast cancer has a high incidence and causes death worldwide, especially in women. Melatonin is a hormone that affects the prevention and treatment of tumors, and its effects have improved when associated with a modified release system. Thus, this study aimed to investigate the effects of a microemulsined system containing melatonin and PEG 400 on cellular oxidative stress and viscosity in the co-culture of blood mononuclear cells (MN) and MCF-7 cells. The microemulsion system containing melatonin and PEG 400 was developed from a mixture of the oil and aqueous phases and stabilized with surfactants. Blood mononuclear cells (MN) obtained from voluntary donors and MCF-7 cells (ATCC) were maintained in culture in CO2 for 24 hours treated with melatonin or with the microemulsion system containing melatonin and PEG 400. The flow and viscosity curves were evaluated using a rheometer, and the oxidative stress was evaluated by superoxide release and superoxide dismutase (SOD) determination by colorimetric methods. The microemulsion system containing melatonin and PEG 400 showed a stable, translucent, and homogeneous property. The viscosity was higher in MCF-7 cells and MN cells when in the presence of a microemulsion system containing melatonin and PEG 400. The rheological behavior of MN and MCF-7 cells did not change in the presence of melatonin. The microemulsion system with melatonin and PEG 400 increased SOD levels in cultures of MN cells co-cultured with MCF-7 cells. These results suggest that the microemulsified system interferes with the oxidative metabolism of MN cells in co-culture with MCF-7 cells, with a reduction in SOD enzyme levels without changing superoxide levels, which could probably be favorable to the antitumor action of blood MN cells.