Human Labour is Associated with a Decline in Myometrial Chemokine Receptor Expression: The Role of Prostaglandins, Oxytocin and Cytokines

Problem: Human labour is an inflammatory process with a heavy infiltration of immune cells into the myometrium and cervix induced by local chemokine production. Myometrial cells also express chemokine receptors, but there is little information about their behaviour or function during pregnancy and labour. Method of Study: We studied the behaviour of the receptors (CCR2, CXCR1 and CXCR2) for the CCL2 and CXCL8 in human myometrium, because both have been shown to be important in labour. Results: We found that there was a significant decline in the mRNA expression of all three receptors in the upper segment and a similar trend in the lower segment with the onset of term labour (TL). Chemokine receptor mRNA expression was increased by stretch, reduced by oxytocin and PGF_2α acting via phospholipase C (PLC). CXCR2 declined with exposure to CXCL8, consistent with the negative relationship observed in labouring myometrial tissue. The mRNA changes were confirmed by western analysis and flow cytometry. Conclusion: These data show that myometrial chemokine receptor expression is reduced with the onset of term labour probably in response to the increased activity of chemokines, oxytocin and PGF_2α.