Pharmacologic doses of interleukin 8 suppositories induce follicular maturation in rabbits

Interleukin 8 (IL-8) is a neutrophil chemoattractant/activating factor that plays a role in the ovarian physiology leads to investigate the effects of IL-8 on follicular maturation. Experiments were conducted using suppositor ies containing 100 ng, 200 ng, 400 ng IL-8, 500 mu l Witepsol-base (control ), human menopausal gonadotropin (im) and conjugate of fluorescein isithioc yanate-abelled IL-8, The levels of IL-8 in ovarian fluid were also measured . Histology of ovaries treated with 200 ng IL-8 showed large antral follicl es filled with follicular fluid. The theca layer was divided into an intern a and an externa with large extracellular spaces, The granulosa cells were loosened and appeared to be detaching from the granulosa layer, Neutrophils were localized predominantly in the theca and medulla (P<0.0001, P<0.004), and relative collagen concentration was significantly decreased in ovaries of 200 ng IL-8 (P<0.0001) compared with controls. The IL-8 was detected in ovarian fluid after 6 h (P<0.0001), 12 h (P<0.001), and 18 h (P<0.01) comp ared with 0 h, Fluorescein isithiocyanate-labelled IL-8 conjugate was seen in the follicular wall and endometrium. We conclude that pharmacological do sage of exogenous IL-8 exerts an effect on follicular maturation through gr anulocyte chemotaxis and activation, (C) 2000 Academic Press.