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

Abstract

The aim of this study was to determine the prostaglandins (PGs) production and ovarian function in gilts after intrauterine infusions of 10 6 and 10 9 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 10 6 or 10 9 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 10 9 cfu/ml induced severe acute or subacute endometritis while 10 6 cfu of E. coli evoked moderate acute endometritis or resulted in no inflammatory changes. In the gilts receiving 10 9 cfu/ml of E. coli, the concentration of 13,14-dihydro-15-keto-PGF 2α in blood from the jugular vein was elevated ( P < 0.05–0.001) compared to concentration in the gilts inoculated with 10 6 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 10 9 cfu/ml, in comparison to 10 6 cfu, resulted in the greater ( P < 0.001) content of PGE 2 in the myometrium. The content of both PGs in the endometrium as well as PGF 2α in the myometrium of gilts-treated with 10 9 cfu/ml of E. coli was lower ( P < 0.001) than in gilts-treated with 10 6 cfu of bacteria. Newly formed corpora lutea were found in the gilts infused with 10 6, but not those infused with 10 9 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 10 9 cfu/ml of bacteria had a higher ( P < 0.05) PGF 2α level and lower ( P < 0.001) PGE 2 level than following infusion of E. coli 10 6 cfu/ml. Also on day 8 of the study, the content of PGE 2 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 10 9 cfu/ml than 10 6 cfu/ml of E. coli. These results indicate that intrauterine infusions of 10 6 or 10 9 cfu/ml of E. coli lead to the development of inflammatory states of different intensities which is connected with different PGF 2α and PGE 2 production and function of ovaries.