The effect of urinary trypsin inhibitor on uterine muscle contraction and cervical maturation

To study the intrauterine defensive role of fetal urine, we focused urinary trypsin inhibitor (UTI) from fetal urine. Urinary trypsin inhibitor (UTI) is a glycoprotein secreted with fetal urine. Until now, its real function has been unknown. The expression of IL-8 induced by LPS were completely abolished in the presence of physiological concentration of UTI in various cells. LPS or IL-8 in the form of vaginal suppositories induced cervical ripening in rabbits. UTI applied after LPS or IL-8 could successfully inhibit the changes induced by IL-8 or LPS in the rabbit cervix. UTI or fetal urine inhibits the increase of intracellular Ca 2+ of uterine muscle cells induced by LPS. Possibly, this regulatory effect of intracellular Ca 2+ is involved in preventing uterine muscle contraction. UTI or fetal urine suppresses premature cervical ripening and prevents uterine muscle contraction. We conclude that UTI of fetal urine is important role in maintaining pregnancy.