Inflammation changes the expression of leukotriene receptors in porcine uteri

Leukotrienes (LTs) are important as pro-inflammatory mediators to the innate immune response, inflammation, and allergy. Although it is known that inflammation of the uterus in gilts leads to an increase in LTB4 and LTC4 synthesis, researchers lack knowledge regarding the expression of LT receptors in the inflamed uterus. The aim of this experiment was to determine the levels of cysteinyl LT receptors type 1 (CysLT(1)R) and type 2 (CysLT(2)R), as well as of LTB4 receptor type 1 (LTB4R1) mRNA and protein expression, and the cellular localization of these receptors in the inflamed porcine uterus. On Day 3 of the estrous cycle (Day 0 of the study), 50 ml of either saline or Escherichia coli suspension (109 colony-forming units/ml) was injected into each uterine horn. Injections of bacteria increased CysLT(1)R mRNA levels in the endometrium on Days 8 and 16 of the study and in the myometrium on Day 16, as well as the CysLT(1)R protein level in the endometrium on Day 8. In the inflamed uteri, CysLT(2)R mRNA levels in the myometrium were increased on Days 8 and 16; however, the protein levels of this receptor decreased in the endometrium (Day 16) and myometrium (Day 8). After bacterial treatment, LTB4R1 mRNA and protein levels in the endometrium on Day 8, and LTB4R1 mRNA levels in the myometrium on Days 8 and 16 were found to have increased. Data obtained show that inflammation of porcine uteri changes the expression of LT receptors, suggesting their importance in the course/consequences of uterine inflammation.