Interleukin-8 release from human gestational tissue explants: Effects of gestation, labor, and chorioamnionitis

Interleukin-8 (IL-8) is a chemotactic cytokine that has been implicated in the process of human parturition, including the processes of cervical ripen ing and rupture of fetal membranes. In this study, the in vitro release of IL-8 from human amnion, choriodecidua, and placenta tissues obtained before and after spontaneous labor onset both at term and preterm, was assessed. The effect of chorioamnionitis on IL-8 release was also established. All ti ssue explants examined released IL-8; however, IL-8 release from choriodeci dual explants was significantly (p < 0.02) greater than that observed from amnion and placenta. Furthermore, choriodecidual IL-8 release was significa ntly (p < 0.001) greater from term tissues (850 +/- 134.4 ng/mg DNA, n = 18 ) than from preterm tissues (458 +/- 68.8 ng/mg DNA, n = 17). Spontaneous o nset of labor, irrespective of the eventual mode of delivery, was not assoc iated with any significant changes in IL-8 release from human gestational t issues compared to not-in-labor tissues, both at term and preterm. IL-8 rel ease from gestational tissues was not significantly different in the absenc e or presence of chorioamnionitis. These data are in contrast to the previo usly reported stimulatory effects of bacterial endotoxin on IL-8 release fr om human gestational tissues. The data are consistent, however, with the su ggestion that IL-8 release is an early event in chorioamnionitis that prece des the appearance of clinically overt symptoms.