Changes in prostaglandin production and ovarian function in gilts during endometritis induced by Escherichia coli infection

The aim of this study was to determine the prostaglandins (PGs) production and ovarian function in gilts after intrauterine infusions of 106 and 109 colony-forming units (cfu)/ml of Escherichia coli (E. coli). In Experiments 1 and 2, 30 ml of saline or 30 ml of E. coli suspension containing 106 or 109 cfu/ml, were infused once into each uterine horn in three groups of gilts on day 3 of the estrous cycle, respectively. In Experiment 1, 17 days after treatment it was revealed that inoculation of E. coli 109 cfu/ml induced severe acute or subacute endometritis while 106 cfu of E. coli evoked moderate acute endometritis or resulted in no inflammatory changes. In the gilts receiving 109 cfu/ml of E. coli, the concentration of 13,14-dihydro-15-keto-PGF2α in blood from the jugular vein was elevated (P < 0.05–0.001) compared to concentration in the gilts inoculated with 106 cfu on days 8–17 after treatment. Both the E. coli-treated groups had a lower (P < 0.05, P < 0.01) progesterone plasma level from days 10 to 14 after administration than the control group. On day 17 of the study, infusion of E. coli 109 cfu/ml, in comparison to 106 cfu, resulted in the greater (P < 0.001) content of PGE2 in the myometrium. The content of both PGs in the endometrium as well as PGF2α in the myometrium of gilts-treated with 109 cfu/ml of E. coli was lower (P < 0.001) than in gilts-treated with 106 cfu of bacteria. Newly formed corpora lutea were found in the gilts infused with 106, but not those infused with 109 cfu/ml of E. coli on day 17 after infusion. On day 8 of the study (Experiment 2), the blood from utero-ovarian vein of the gilts-treated with 109 cfu/ml of bacteria had a higher (P < 0.05) PGF2α level and lower (P < 0.001) PGE2 level than following infusion of E. coli 106 cfu/ml. Also on day 8 of the study, the content of PGE2 in the endometrium, both the PGs in the myometrium as well as cyclooxygenase-2 in the endometrium and myometrium was greater (P < 0.01, P < 0.001) after applying 109 cfu/ml than 106 cfu/ml of E. coli. These results indicate that intrauterine infusions of 106 or 109 cfu/ml of E. coli lead to the development of inflammatory states of different intensities which is connected with different PGF2α and PGE2 production and function of ovaries.