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Mare endometrium : physiological and pathological involvement of hormones and neutrophil extracellular traps
Publication . Crisóstomo, Maria Rosa Rebordão Cordeiro Simões; Dias, Graça Maria Leitão Ferreira
Two reproductive topics in mares were addressed in this thesis. The aims of the studies were
to evaluate: (i) the effect of chronic oxytocin administration to mid-luteal phase mares on
luteal maintenance and its cellular and molecular mechanisms at endometrial level; (ii) the
capacity of equine neutrophils to produce neutrophil extracellular traps (NETs) in vitro when
stimulated with bacteria obtained from mares with endometritis, and to determine if NETs
release also occurred in vivo in mares with endometritis; (iii) the in vitro effects of some
NETs components on mare endometrial fibrogenic capacity and to determine if they could
depend on endometrial inflammatory lesions or estrous cycle phases; and (iv) the involvement
of PGF2α and PGE2 pathways in collagen deposition on mare endometrium, challenged with
NETs proteases. In the first study, luteal maintenance occurred in 67% of oxytocin treated
mares, which may be related to oxytocin and progesterone (PGR) receptors spatial expression
in endometrium. Reduction of endometrial estrogen receptor 2 (ESR2) may be responsible for
the maintenance of PGR in luminal and glandular epithelium and may attenuate ESR1
endometrial transcriptional activity. Equine neutrophils were able to release NETs in the
presence of bacteria that cause mare endometritis, and might be a complementary mechanism
to fight endometritis. By in vitro studies with NETs proteases, increased collagen type I
(COL1) production characteristic of fibrosis was observed, although endometrial response to
each NETs protease depended on estrous cycle and/or endometrial category. Also, NETs
proteases were linked to fibrogenesis, by increased synthesis of PGF2a and/or PGF2a
receptor transcripts and impaired PGE2 or PGE2 receptor 2 transcripts associated to increased
COL1. These effects were influenced by endometrium type and estrous cycle phases. Injury
induced-changes on PG mediators by NETs components may instigate PGF2α or PGE2 vias,
as additional pathways in mare endometrial fibrogenesis.
Involvement of hormones, cytokines and angiogenic factors on mare oviduct physiological function and fibrosis
Publication . Bravo, Pedro Nuno d’Almeida Monteirinho Pinto; Dias, Graça Maria Leitão Ferreira; Costa, Rosário Plácido Roberto da
The oviduct is a very important organ of the female reproductive system, as it plays a crucial role in providing the ideal conditions for the final preparation of the gametes for fertilization and to support the early embryo development. This work contributed to: (i) clarify the role of ovarian steroid hormones, oxytocin (OXT) and TNFα on the modulation of oviduct prostaglandin secretion; (ii) relate the expression of angiogenic growth factors during angiogenesis, with oviductal function; (iii) evaluate the expression of OVGP1 throughout the estrous cycle in the mare; (iv) and to investigate the expression of collagen in equine oviduct and its correlation with endometrial fibrosis and possible pathways involved. Post-mortem tissues were used for experimental works, such as histological stains, immunohistochemistry (IHQ), western blot analysis, qPCR evaluation, enzyme immunoassay, oviduct epithelial cells and tissue explants in vitro culture. In equine oviduct, ESR1, ESR2, PGR, OXTR, PTGES and AKR1C3 mRNA and protein expression was estrous cycle dependent and varied with oviduct portions. Ovarian steroid hormones, OXT and TNFα stimulation of PGF2α and/or PGE2 production also depended on estrous cycle dependent and changed in the different portions of oviduct. In addition, protein and mRNA expression of FGF, VEGF and their receptors differed throughout the estrous cycle and between oviduct portions and agreed with changes in microvascular density and/or oviductal secretory function. Oviduct glycoprotein 1 (OVGP1) transcription presented differences throughout the oviduct portions, and in different phases of estrous cycle. A higher expression was observed in isthmus and during follicular phase (P < 0.05). Also in the follicular phase, OXT and TNFα upregulated OVGP1 transcription; in the early luteal phase, estradiol (E2), while in mid luteal phase, it was progesterone (P4) that stimulated its transcription. However, OVGP1 in vitro production was not dependent of E2, P4, OXT or TNF treatments in any oviduct portion. Furthermore, sperm cells also up-regulated OVGP1 production, in isthmus, in early luteal phase (P < 0.05). COL1 and COL3 transcription in isthmus was correlated with the correspondent transcription in the endometrium. Particularly in isthmus, AKR1C3 was implicated with collagen transcription (P < 0.05). Collagen transcription in isthmus was correlated with MMPs transcription in endometrium (P < 0.05). Thus, in the mare, endometrium fibrosis appears to reflect collagen deposition in the oviduct.
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Fundação para a Ciência e a Tecnologia
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3599-PPCDT
Número da atribuição
PTDC/CVT/121805/2010