Effect of oxygen tension on bacteria-stimulated cytokine production by fetal membranes.

AIM

Tissue culture studies indicate that bacterial products stimulate the production of proinflammatory cytokines by reproductive tissues. However, most of these studies have been performed under room air conditions, supplemented with 5% CO₂. In this study, we tested whether O₂ tension affects bacteria-stimulated cytokine production by extra-placental fetal membranes.

METHODS

Cultures of full-thickness membranes, isolated choriodecidua, and isolated amnion were exposed to bacteria and incubated under 21% (room air) or 5% O₂ for 18 h. Cytokine concentrations in conditioned medium was quantified by immunoassay.

RESULTS

Culture under 5% O₂ increased production of interleukin (IL)-1β and tumor necrosis factor (TNF)-α, but reduced IL-10 and IL-6 production by full membranes. Isolated choriodecidua responded to 5% O₂ with increased IL-1β production and reduced IL-6 production, but had no effect on TNF-α and IL-10 production was not detected. No effect of O₂ tension on IL-1β or IL-6 production by isolated amnion was detected, however, Escherichia coli-stimulated IL-10, TNF-α and IL-8 production was enhanced by culture under 5% O₂.

CONCLUSIONS

Increased oxygen tension reduces the pro-inflammatory responsiveness of cell cultures to E. coli and promotes an anti-inflammatory cytokine profile. Differential effects of O₂ tension on choriodecidua and amnion suggests a network of paracrine factors that regulate cytokine levels in response to changes in O₂ tension.