The effect of transforming growth factor and interleukin-10 on interleukin-8 release by human amniochorion may regulate histologic chorioamnionitis.

OBJECTIVE

Amniochorion is a source of interleukin-8 during infection and inflammation. In this study we investigate the role of 2 immunoinhibitory cytokines, transforming growth factor and interleukin-10, in regulating interleukin-8 production from human fetal membranes and define their mechanism of regulation.

STUDY DESIGN

Amniochorion was placed in an organ explant system for 72 hours. Tissues were stimulated with lipopolysaccharide (50 ng/mL), lipopolysaccharide plus transforming growth factor-beta (50/50, 50/100), transforming growth factor-beta (50 and 100 ng/mL), lipopolysaccharide plus interleukin-10 (50/50 and 50/100), and interleukin-10 (50 and 100 ng/mL) in culture. Tissue and media samples were frozen until quantitation of interleukin-8 messenger ribonucleic acid and protein. Quantitation of messenger ribonucleic acid was performed by quantitative competitive polymerase chain reaction and protein by enzyme-linked immunoassay, respectively.

RESULTS

Lipopolysaccharide-stimulated tissues produced approximately 6 x 10(6) molecules per microliter of interleukin-8 messenger ribonucleic acid compared with 6 x 10(3) molecules per microliter in controls. Transforming growth factor-beta alone and lipopolysaccharide plus transforming growth factor-beta stimulation produced 6 x 10(5) and 6 x 10(4) molecules of interleukin-8 messenger ribonucleic acid per microliter, respectively. Tissues stimulated with lipopolysaccharide plus 50 ng/mL interleukin-10 produced approximately 600 molecules per microliter of interleukin-8 messenger ribonucleic acid, whereas no amplifiable messenger ribonucleic acid was detected in tissues treated with lipopolysaccharide plus 100 ng/mL interleukin-10. Tissues treated with interleukin-10 alone produced 6 x 10(3) molecules of messenger ribonucleic acid, similar to control levels. Enzyme-linked immunosorbent assay data showed similar levels of interleukin-8 peptide release from lipopolysaccharide and lipopolysaccharide plus transforming growth factor-beta-treated fetal membranes. A dose-dependent decrease in interleukin-8 peptide release was seen in tissues treated with lipopolysaccharide plus interleukin-10, whereas stimulation with transforming growth factor or interleukin-10 alone resulted in interleukin-8 peptide release similar to that of control levels.

CONCLUSION

Transforming growth factor-beta seems to have no effect on interleukin-8 protein production in the presence of an infectious agent; however, a drop in messenger ribonucleic acid levels was observed. Interleukin-10 in the presence of lipopolysaccharide showed down-regulation of interleukin-8 messenger ribonucleic acid expression and peptide production. These data suggest that fetal membrane interleukin-8 production can be controlled by interleukin-10 during an infectious process.