Synthesis of prostacyclin and its effect on the contractile activity of the inflamed porcine uterus.

The goal of the study was to estimate the content of prostacyclin (PGI(2)), the levels of PGI synthase (PTGIS) and receptor (PTGIR) protein expression, and the cellular localization of these factors in the inflammatory-changed porcine uterus. The effect of PGI(2) on the contractility of the inflamed uteri was also determined. On Day 3 of the estrous cycle (Day 0 of the study), 50 mL of either saline or Escherichia coli suspension (10(9) colony-forming units/mL) were injected into each uterine horn. Acute endometritis developed in all bacteria-inoculated gilts, however on Day 8 of the study a severe form of acute endometritis was noted more often than on Day 16. Bacteria injections increased the contents of 6-keto-prostaglandin F(1α) in endometrium, myometrium, washings, and the level of PTGIS in endometrium on Days 8 and 16, and the content of PTGIR in endometrium on Day 16. In the inflamed uteri on both study days, stronger immunoreactivity for PTGIS was observed in part of the luminal and glandular epithelial cells and in a portion of the endometrial arteries, and for PTGIR in part of the luminal epithelium and endothelial cells in a portion of the endometrial arteries. On Day 8, PGI(2) decreased contraction intensity in endometrium/myometrium and myometrium of the saline-treated uteri and increased the contraction intensity in both types of strips from the inflamed organs. Our study reveals that inflammation of the porcine uterus upregulates PGI(2) synthesis and that PGI(2) increases contractility, which suggests that PGI(2) might be essential for the course of uterine inflammation.