Sleep Deprivation Alters T Cell Dynamics: Melatonin as a Restorative Agent

Sleep is an essential physiological function regulated by circadian rhythm and homeostatic regulation for emotional and physical health. Conversely, sleep deprivation (SD) is associated with weakened immune system function and overall health, which potentially leads to chronic diseases such as heart disease and diabetes. In this study, we aimed to investigate the role of regulatory T cells (Tregs) in the immune response to SD and the potential therapeutic effect of melatonin in modulating this response. For this purpose, 24 8-week-old male C57BL/6J mice were distributed into 4 groups: control, control with melatonin, SD, and SD with melatonin. Treg levels were assessed in peripheral blood and spleen samples with flow cytometry. According to the data, SD decreases the CD3⁺ T cells in blood but not in spleen samples. Moreover, Helios transcription factor expressing Treg cell levels are increased in both blood and spleen in the SD group, which indicates a possible immunosuppressive occurrence. Melatonin administration affected the numbers of total Tregs and particularly the numbers of Helios⁺ Tregs and restored the T cell population similar to the normal levels. Our results suggest melatonin as a key regulatory component for SD-induced immunological imbalance as well as reduced memory and effector Tregs and increased naïve Tregs. According to these findings, they highlight the immunological consequences of SD and the therapeutic promise of melatonin in restoring immune function.