Efeito da melatonina sobre a expressão do cd16 e cd56 sobre células nk do colostro

Abstract

Breast milk has nutrients that help the newborn's growth, it is presented as colostrum, a product resulting from lactogenic hormones, which contains important components such as melatonin and defense cells, including Natural Killers (NK). The hormone Melatonin, secreted in milk, regulates the neonate's Cincardian cycle, in addition to its immunomodulatory functions, further increasing the activity of defense cells. NK cells show spontaneous cytotoxic activity for tumors, viruses. The expression of NK cells occurs through their “clusters of differentiation” (CD), being CD16 and CD56. Breastfeeding is fundamental for the adaptation of the newborn in the extrauterine environment, in addition to being benefits conferred to the newborn, studies report the maternal benefits of this act, among them, a lower risk of developing breast cancer stands out, a of the most incident types of cancer. The present study aimed to evaluate the expression of colostrum NK cells, in co-culture or not with MCF-7 cells in the presence of the hormone melatonin. Colostrum samples were collected from nursing mothers (n = 10) in the city of Barra do Garças - MT. To evaluate the expression of NK cells in the different experimental groups, the immunophenotyping method was used, analyzed by flow cytometry, acquisition and analysis of the data obtained by the CellQuest software. Melatonin contributed mainly to the expression of the CD56 marker, whereas MCF-7 cells contributed to the expression of the CD16 marker. In the co-cultures of NK cells with MCF-7, melatonin substantially stimulated the expression of both markers, CD16 / 56 (NK cells). These findings reinforce breastfeeding, and melatonin as one of the components of breast milk that acts as an immunomodulator, can reduce the incidence of breast cancer, in addition to other components that assist in this same effect and in the prevention of several other infections that may affect the neonate.