Hormone-producing role of mast cells in reproductive processes: myth or reality?

The role of mast cells in the onset and progression of endocrine system dysfunction has been studied for quite a long time, but a clear understanding of their participation has not been obtained. The purpose of the study was to consider the hormone-producing and cytokine-producing functions of mast cells in primary culture in various environments simulating certain hormonal conditions, modeling the level of hormones in follicular fluid during ovulation, to identify the participation of mast cells in the development of endocrine diseases, and to discover new functions of mast cells. A continuous line of human mast cells HMC-1 (Human mast cell, ATCC) was used, being cultured in IMDM medium (Dulbecco’s modified Eagle’s medium, Sigma-Aldrich). Medium 1 (IMDM) served as a control; medium 2 was an IMDM medium supplied with hormones simulating follicular fluid during ovulation in healthy women, and medium 3 (IMDM) was supplied with hormones mimicking follicular fluid during ovulation in polycystic ovary syndrome. The content of progesterone, testosterone, estradiol, IL-6 was measured on days 1,3,7 of experimental cultures. Hormonal pattern in the mast cell cultures changed depending on the microenvironment and duration of experiment. The level of estradiol in medium 1 increased more than 80 times compared to the level of estradiol before initiation the cultures. Incubation in medium 2 was followed by 40-fold increase in estradiol by the 7th day of experiment. In medium 3, estradiol levels increased more than 35 times. Testosterone level increased in medium 1 by 3 times; in medium 2, 2.5-fold by the day 7. Upon culture in medium 3, testosterone levels increased 8-fold. IL-6 levels in all media with mast cell culture increased by day 7, but did not exceed the physiological ranges of the cytokine. A significant progressive increase in the contents of estradiol, testosterone and IL-6 in continuous culture of HMC-1 mast cells observed in different culture media simulating certain in vivo hormonal background suggests an active participation of mast cells in reproductive processes and an independent de novo synthesis of sex steroids and IL-6 by mast cells, which, however, requires a number of confirmatory experiments.