Effect of Progesterone on the <i>in vitro</i> Response of Peripheral Blood Mononuclear Cells Stimulated by <i>Escherichia coli</i> in Mares

Abstract

ABSTRAcT. Escherichia coli(E. coli) isolated from the uterus of a Thoroughbred mare with bacterial endometritis was used to evaluate the effect of progesterone (P 4 ) on the immune response of mares. Peripheral blood mononuclear cells (PBMcs) were collected from 10 nonpregnant clinically healthy adult mares (range, 4-12 years) during diestrus, four Thoroughbreds and six Hokkaido native horses. Cell proliferation and expression of cytokine mRNA, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-10, of PBMcs stimulated with E. coli and P 4 were examined in vitro. P 4 was shown to have significantly inhibited E. coli induced proliferation and expression of IFN-γ in PBMCs. These results indicate that P 4 inhibits the immune response to E. coli in mares. KEY WORDS: bacterial endometritis, cytokine, Escherichia coli, mare, progesterone.doi: 10.1292/jvms.11-0364; J. Vet. Med. Sci. 74(5): 629-632, 2012 Endometritis is the third most common medical condition in horses [28] that causes infertility and results in major losses in the equine breeding industry. To date, bacterial uterine infection has been reported to occur in 25-60% of barren mares [2,5,7] and Escherichia coli(E. coli) are most frequently associated with fertility problems in mares [1]. It was reported that the endometrium of the mare shows an enhanced ability to eliminate infection during the follicular phase compared with the luteal phase of the estrous cycle [14]. Previous studies suggest that progesterone (P 4 ) is closely associated with the incidence of bacterial endometritis and that P 4 dominated uterus exhibits reduced physical clearance of bacteria in the mare [10]. These findings suggest that P 4 significantly affects the incidence of endometritis.Inflammation is initiated and maintained by the emergence of a network of proinflammatory cytokines, such as interferon (IFN)-γ and tumor necrosis factor (TNF)-α, and anti-inflammatory cytokines, such as interleukin (IL)-10 [24]. Recently, Fumuso et al. [12,13] reported that mares susceptible to developing persistent endometritis have higher endometrial expression of proinflammatory cytokines and lower levels of the anti-inflammatory cytokines. In addition, Watson et al. [30] reported that mares with elevated plasma concentrations of P 4 had decreased bactericidal activity of neutrophils in the uterus. Also, in anestrus dogs, P 4 caused significant inhibition of the proliferation of peripheral blood mononuclear cells (PBMcs) in response to E. coli isolated from the uterus affected by pyometra [27]. Progesterone inhibits the proliferation of peripheral blood lymphocytes activated by mitogens in humans [22], cows [3], sheep [16] and pigs [31]. Progesterone treatment of mares has been associated with prolonged infection after intrauterine inoculation with bacteria [4,14]. These reports in different species indicate that not only the status of systemic immunity affected by P 4 was associated with bacterial growth in the uterus but also that the immunosuppressive effects of P...

The Effect of Progestins on Cytokine Production in the Peripheral Blood Mononuclear Cells of Menopausal Women and Their Luminol-Dependent Chemiluminescence

“…The obtained data about P4 inhibitory activity are in good accordance with previously obtained results on E. coli-stimulated horse PBMCs: P4 (1 µg/mL or 0.3 µM) inhibited PBMC viability by approximately 30% [13].…”

Infection and Infertility in Mares

“…The organisms most frequently isolated from mares with acute endometritis are S. zooepidemicus (β-hemolytic), E. coli (haemolytica), P. aeruginosa, and K. pneumoniae [2,[58][59][60].…”

>b<Efeito da suplementação hormonal com progestágenos em éguas prenhes sobre os hormônios tireoidianos e esteroides dos neonatos>/b<

“…Sob a sua prevalência no ambiente uterino foi observada maior proliferação de bactérias mesmo havendo acúmulo de leucócitos, sugerindo um atraso na mobilização das células de defesa, tal como ocorre em outras espécies (EVANS et al, 1986;HANSEN, 1998). A ocorrência de downregulation na atividade dos linfócitos frente a antígenos foi comprovada por Maeda et al (2012).…”