The influence of leukotrienes C 4 and D 4 on the contractility of an inflamed porcine uterus B. Jana a, * , J.J. Jaroszewski b , J. Czarzasta a , W. Markiewicz b a Division of Reproductive Biology, Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Olsztyn, Poland b Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland article info Article history: Received 18 June 2014 Received in revised form 19 January 2015 Accepted 20 January 2015 Keywords: Uterine contractility Inflammation Leukotrienes Gilts abstract The effect of leukotriene (LT) C 4 (LTC 4 ) and LTD 4 on the contractility of an inflamed porcine uterus was investigated. On Day 3 of the estrous cycle (Day 0 of the study), either saline or Escherichia coli suspension was injected into each uterine horn. Although acute endome- tritis developed in all bacteria-inoculated gilts, a severe acute endometritis was noted more often on Day 8 than on Day 16. Myometrial and endometrial/myometrial strips were incubated with LTC 4 or LTD 4 alone, or together with a cysteinyl-LT receptor antagonist (BAY-u9773). Leukotriene C 4 increased the contraction intensity in the saline- and bacteria-treated uteri on Day 8; however, its effect was lower in the myometrium of inflamed uteri. Contraction frequency was found to decrease in the saline-treated uteri as opposed to inflamed ones, in which it was elevated. On Day 16, contraction intensity increased in response to LTC 4 in the saline-treated uteri but was reduced in the inflamed organs. The value of this parameter was lower in the inflamed uteri than that in the saline- treated ones. Leukotriene D 4 (Days 8 and 16) augmented contractility in the saline-treated uteri, but despite increasing its intensity in the inflamed organs, it decreased contraction frequency. Leukotriene C 4 or LTD 4 , added to BAY-u9773–pretreated saline- and bacteria- treated uteri on both days, decreased the contraction intensity. On Day 16 after treat- ment with BAY-u9773 and LTC 4 , contraction intensity in the endometrium/myometrium of the inflamed uteri was lower than that in the saline-treated organs. Data show that both LTC 4 and LTD 4 affect the contractility of inflamed porcine uteri, though LTC 4 exerts a weaker contractile effect. Ó 2015 Elsevier Inc. All rights reserved. 1. Introduction Uterine inflammation is a reproductive disorder that is common to female domestic animals and responsible for considerable economic losses. This pathologic state is caused mainly by bacterial microorganisms [1–3]. Endo- metritis/metritis can occur in the females that have not yet given birth and after insemination or natural mating. However, it most often develops after parturition as a consequence of impaired uterine involution and/or immunologic response [4]. Difficult labor, uterine atony, and fetal membrane retention all promote the develop- ment of uterine inflammation. A mild course of inflam- mation evokes no serious disturbances in the estrous cycle. More severe cases, however, can lead to the uterus becoming filled with mucopurulent exudate. The uterine muscular layer of affected animals, particularly cows, loses its ability to contract [1,5,6]. In such events, intensive therapy is not always successful, though a wide variety of treatments are available for uterine inflammation (endo- metritis/metritis). These include systemically or locally administrated antibiotics, the systematic injection of prostaglandin (PG) PGF 2a , and intrauterine-administered * Corresponding author. Tel.: þ48 89 53574 37; fax: þ48 89 5357421. E-mail address: b.jana@pan.olsztyn.pl (B. Jana). Contents lists available at ScienceDirect Theriogenology journal homepage: www.theriojournal.com 0093-691X/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.theriogenology.2015.01.021 Theriogenology 83 (2015) 1328–1337