Mechanical stretch of human uterine smooth muscle cells increases IL-8 mRNA expression and peptide synthesis.
Labour is associated with increased synthesis of interleukin-8 (IL-8) by the fetal membranes and myometrium, which leads to an inflammatory infiltrate. Stretch has been shown to increase the expression of contraction-associated proteins in animal models of labour and in human myocytes in vitro. In this study, we tested the hypothesis that mechanical stretch of human myometrial cells increases IL-8 messenger ribonucleic acid (mRNA) expression. We isolated myocytes from non-pregnant women undergoing hysterectomy and pregnant women undergoing Caesarean section before and after the onset of labour. Myocytes in culture were subjected to stretch of varying intensity (6-16%) and duration (1 or 6 h) using the Flexercell system. IL-8 mRNA expression was lowest in myocytes from pregnant women not in labour, intermediate in those from non-pregnant women and greatest in those from pregnant women in labour. Stretch increased IL-8 mRNA expression independent of reproductive state. The stretch-induced increase in IL-8 mRNA expression was associated with higher IL-8 levels in the culture supernatant and enhanced promoter activity. These data suggest that stretch contributes to the increase in myometrial IL-8 synthesis associated with the onset of labour in humans.
Loudon
J A Z
JA
Imperial College Parturition Research Group, Hammersmith Hospital Campus, DuCane Road, London W12 0NN, UK.
Sooranna
S R
SR
Bennett
P R
PR
Johnson
M R
MR
D005260:Female; D015870:Gene Expression; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D015854:Up-Regulation; D014590:Uterine Contraction / Q000235:genetics; D014599:Uterus / Q000166:cytology / Q000378:metabolism*
D016209:Interleukin-8; D010455:Peptides; D012333:RNA, Messenger