Progesterone modulates the expression of interleukin-6 in cultured term human uterine cervical fibroblasts

The preventative value of progesterone in preterm labor has been recently recognized, especially when it is administered via vaginal suppository. This study was undertaken to evaluate the effect of progesterone on interleukin-6 (IL-6) production in human uterine cervical fibroblasts (UCFs) treated with lipopolysaccharides (LPS).

Human uterine cervical tissue was obtained at term, prior to the onset of labor, during the scheduled cesarean section or cesarean hysterectomy. Primary UCF cultures were established and confirmed by immunohistochemistry. IL-6 mRNA and protein expressions were examined by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.

Lipopolysaccharides stimulation induced a clear time- and dose-dependent increase in IL-6 mRNA and protein levels in UCFs (P < 0.05). Progesterone treatment significantly attenuated LPS-induced increases in IL-6 mRNA and protein expressions in UCFs (P < 0.05). Estrogen exposure had no effect on LPS-induced IL-6 up-regulation and did not modulate the effects of progesterone.

Our preliminary results suggest that vaginal progesterone might prevent spontaneous preterm labor through a mechanism involving anti-inflammatory effects on UCFs, particularly suppression of IL-6 production.