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Abstract: Systemic and local infections and inflammations are known to cause infertility in humans and animals. However, the mechanisms by which infection/inflammation induces infertility are only partially known. The objectives of this study were: (i) to provide models of systemic (acute) and local (sub-acute) inflammation by intra-peritoneal injection or intra-cervical deposition of lipopolysaccharide (LPS) in the rabbit and (ii) to assess their effects on uterine tissues and sperm transport in the genital tract of rabbit does. Intra-peritoneal administration of different doses of LPS induced systemic effects such as fever, anorexia and changes in white blood cells (WBC) count. In our study, LPS inoculation (100μg/kg) produced an inflammation-like status that lasted for about 3 days, with minimal distress for the animals. Intra-peritoneal administration of LPS 60h before artificial insemination induced a rapid increase of IL-1β concentrations. The intra-cervical inoculation of LPS did not show any systemic effects, as confirmed by the lack of changes in body temperature, feed intake and WBC count. Histological examination of uterine tissues showed an endometritis-like inflammation status in LPS-treated does, more severe in those inoculated intra-cervically. The number of spermatozoa recovered from uterine horns and oviducts of intra-cervically treated does was less than that retrieved from intra-peritoneally treated animals and controls. These results suggest (i) that sub-acute or acute inflammation may cause infertility by compromising the uterine environment and/or impairing sperm transport and (ii) that the LPS-induced -infection/inflammation experimental model is useful for studying the mechanisms involved in reproductive dysfunctions in the rabbit. [Copyright &y& Elsevier]

This study was conducted to evaluate the changing concentrations of metabolic hormones and metabolites in pregnant (P) and pseudopregnant (PP) rabbit does. Twenty-five New Zealand White rabbit does were submitted to artificial insemination (AI) and then classified as P (n = 15) or PP (n = 10). Blood samples were collected weekly until day 32 post AI. During pregnancy, leptin concentrations were greater on Days 14 and 21 (P < 0.05), while insulin was greater on days 21 and 32 post AI (P < 0.05) compared to PP does. The triiodothyronine/thyroxine (T3/T4) ratio was greater in the first and last week (P < 0.001); whereas, cortisol concentrations were greater in the last week of pregnancy and after parturition (P < 0.01) compared with that of PP does. Non-esterified fatty acids (NEFA) concentrations increased from day 7 until day 32 post AI (P < 0.05). Glucose concentrations were unchanged throughout pregnancy although concentrations were positively associated with litter size. These results indicate concentrations of hormones and metabolites change during pregnancy to ensure energy requirements are met for both the foetuses and the maternal tissues. Physiological hyperleptinemia, hyperinsulinemia, and changes in cortisol as well as thyroid hormones indicate there is an adaptation of metabolic functions induced by pregnancy. These adaptations could be mediated by gonadal steroids because changes mainly occur in the second half of pregnancy when the profile of the sex hormones differs between P and PP does., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The study was designed to examine the aglepristone (RU534) mechanisms affecting the corpora lutea (CL) lifespan in pseudopregnant rabbits. Aglepristone (10 mg/kg b.w.) was injected subcutaneously twice at either early- or mid-luteal phase (Days 3 and 4, or Days 8 and 9, respectively) after induction of ovulation with GnRH (Day 0). Corpora lutea and uteri, explanted at days 6 and 11, were evaluated for immunohistochemistry and Western blotting of progesterone (PR) and estrogen (ER) receptors, cyclooxygenase 1 (COX1), COX2, and PGE2-9-ketoreductase (PGE2-9-K) enzymatic activities, and progesterone, PGF2α, and PGE2 in vitro synthesis. Independent of luteal stage, aglepristone prolonged the functional luteal phase by 3 Days over that of controls as assessed by blood progesterone profiles. Aglepristone decreased protein for ER during both luteal-stages in CL and uteri. Progesterone receptor protein was decreased by RU354 at Days 6 in the uterus and at Days 11 in CL, whereas RU534 increased PR at Days 11 in uteri. In the CL, RU534 enhanced progesterone production at Days 6 and 11, whereas it decreased PGF2α and increased PGE2 at Day 11. In the uteri, RU534 decreased PGF2α and increased PGE2 synthesis at both days. COX2 and PGE2-9K activities were decreased by RU534 in the CL at Day 11, whereas in the uteri COX2 increased and PGE2-9-K decreased at Days 6 and 11. In conclusion, these data on aglepristone effects suggest that progesterone has a regulatory role on luteal function through direct and uterine-mediated mechanisms in pseudopregnant rabbits., (Copyright © 2013 Elsevier B.V. All rights reserved.)