Alteration of secretory leukocyte protease inhibitor in human myometrium during labor

Objective Secretory leukocyte protease inhibitor (SLPI) has been shown to have antimicrobial and antiinflammatory properties. The aim of this study was to verify its expression in human myometrium. Study Design Myometrium was obtained at time of cesarean delivery with (n = 9) or without (n = 11) labor. Expression of SLPI was detected using real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry. SLPI expression relative to nuclear factor-κB p65 subunit was compared between subjects. SLPI response to inflammatory mediators was studied in myometrial explants. Results SLPI was predominantly localized in the nuclei of myocytes and colocalized with CD68+ macrophages. The nuclear immunoreactivity of SLPI was increased after the onset of labor and was associated with increased nuclear translocation of nuclear factor-κB p65 subunit. Treatment with lipopolysaccharide, interleukin-1β, or tumor necrosis factor-α increased SLPI messenger RNA and protein concentrations slightly in myometrium explants. Conclusion SLPI was expressed in human myometrium and increased after the onset of labor.