Quantitation and localization of inflammatory cytokines interleukin-6 and interleukin-8 in the lower uterine segment during cervical dilatation

Purpose: Cervical dilatation during parturition is associated with a significant increase of interleukin (IL)-6 and IL-8. The purpose of this study was to localize the respective messenger RNA and to quantitate their protein levels during various stages of dilatation. Methods: Protein extracts from 34 biopsy specimens of the lower uterine segment at various stages of cervical dilatation (<2, 2 to <4, 4-6, and >6 cm) were subjected to enzyme linked immunosorbent assay for IL-6 and IL-8 to document their concentration. The respective mRNA expression was studied using reverse transcriptase PCR using IL-6 and IL-8 specific primers. Localization of IL-6 and IL-8 was done by in situ hybridization using biotinylated probes. Results: The IL-6 and IL-8 concentrations increased significantly in the lower uterine segment tissues at 4-6 cm of dilatation. Expression of IL-8 was seen in all the tissues at or more than 4 cm dilatation, whereas IL-6 expression was inconsistent. In situ hybridization localized IL-6 and IL-8 mRNA to the glandular epithelium. Conclusions: The increase in the inflammatory cytokines (IL-6 and IL-8) during parturition is associated with cervical effacement.