Evidence for a neutrophil-interleukin-8 system in human folliculogenesis

OBJECTIVE: This study was conducted to determine whether polymorphonuclear leukocytes (neutrophils) and the potent chemoattractant interleukin-8 are associated with follicle development in the normal human ovary. STUDY DESIGN: We performed a morphometric analysis of neutrophils in 268 human ovarian follicles, of which 199 were preantral and 69 were antral. In each antral follicle the numbers of mitotic, apoptotic, and total granulosa cells were counted to determine healthy and atretic follicles. Interleukin-8 protein and messenger ribonucleic acid were detected by immunohistochemistry and in situ hybridization, respectively. RESULTS: Antral follicles contained relatively large numbers of neutrophils within the theca vasculature. The density of neutrophil was twofold greater (p < 0.05) in atretic versus healthy follicles. The neutrophil index (neutrophils/granulosa cells x 1000) was inversely correlated to the number of granulosa cells per follicle. Immunoreactive interleukin-8 was detected in the theca and granulosa cells of most all antral follicles examined. Interleukin-8 messenger ribonucleic acid was demonstrated in theca and granulosa cells of some but not all follicles examined. CONCLUSIONS: Neutrophils are present in the theca of developing antral follicles, increase in number during atresia, and are associated with expression of interleukin-8 in the follicle wall.