Gonadotropin- and cytokine-regulated expression of the chemokine Interleukin 8 in the human preovulatory follicle of the menstrual cycle

Interleukin 8 (IL-8) is a chemotactic cytokine involved in the recruitment and activation of neutrophils as well as in cell proliferation and angiogen esis. Because these events are essential components of folliculogenesis, ov ulation, and subsequent repair of the ruptured follicle, the presence and r egulation of IL-8 in the human follicle of the menstrual cycle was investig ated. The concentrations of IL-8 were higher in follicular fluids from domi nant follicles of late follicular/ ovulatory phase compared with those of m idfollicular phase. IL-8 was detected in the media from cultured granulosa and theca cells, with 10-fold higher levels in the theca cell cultures. Exp osure to FSH and LH increased the IL-8 secretion from granulosa cells, but no effect was seen in theca cell cultures. Estradiol and progesterone did n ot affect IL-8 secretion from any cell type. The cytokines IL-1 alpha and I L-1 beta, but not tumor necrosis factor alpha, enhanced IL-8 secretion fi o m both cell types. IL-8 levels in cultures of granulosa-lutein cells from h yperstimulated in vitro fertilization cycles were not affected by either go nadotropins or steroids. These data provide evidence that ovarian IL-8 is g onadotropin and cytokine induced and may be involved in the hormonally regu lated stages of follicular development and ovulation.