Labour-associated increase in interleukin-1 alpha release in vitro by human gestational tissues

The aims of this study were to investigate the concentration and release of interleukin-1 alpha (IL-1 alpha) at the time of human term labour, and to study the regulation of IL-1 alpha release from human gestational tissue explants by bacterial endotoxin. Immunoreactive IL-1 alpha concentrations in maternal plasma, amniotic fluid and conditioned media from human amniotic fluid and conditioned media from human amniotic, choriodecidual and placental explants were quantified before and after spontaneous term labour-onset and delivery. Furthermore, the effects of a bacterial endotoxin, lipopolysaccharide (LPS), on the release of IL-1 alpha from human gestational tissue explants over a time course of 24 h (n = 3) and LPS concentrations ranging from 10-10(7) pg/ml (n = 3) were investigated. IL-1 alpha concentrations in maternal plasma and amniotic fluid did not change significantly with spontaneous term labour-onset. In contrast, IL-1 alpha was released in detectable amounts from human amniotic and choriodecidual explants only in association with term labour-onset and delivery. Similarly, placental release of IL-1 alpha was increased significantly in explant cultures in association with term labour-onset and delivery. LPS increased IL-1 alpha release significantly only from human placental explants from both term not-in-labour and term after-labour tissues. The data demonstrate differential regulation of IL-1 alpha release from human gestational tissues in association with labour and LPS treatment and the observations support the hypothesis that the labour-associated increase in IL-1 alpha release from the fetal membranes is independent of exposure to bacterial endotoxin.