Defective secretion of Prostaglandin F2α during development of idiopathic persistent corpus luteum in mares

Ginther, O.J.; Castro, T.; Baldrighi, J.M.; Wolf, C.A.; Santos, V.G.

doi:10.1016/j.domaniend.2015.10.004

Cited by 8 publications

(8 citation statements)

References 18 publications

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“…The absence of a tendency for increased IOI in the mares reported by Aurich et al (24) could have been the result of discontinuous ZON exposures (alternating cycles). Frequency of the incidence of persistent CLs (10%) was similar to the reported naturally occurring frequency of −10% in the peak of the ovulatory season (38,39). There were no clear treatment effects on the biopsy results, and higher scores for older mares have been reported in the literature (40).…”

Section: Discussionsupporting

confidence: 77%

Reproductive Performance of Mares Fed Dietary Zearalenone

et al. 2019

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It is known that zearalenone (ZON) interacts directly with estrogen receptors, and its in vivo effects on reproduction have been well-documented in several species. In contrast, reports of ZON's impact on horse reproduction are conflicting and inconclusive, some studies confounded by the presence of mycotoxins such as deoxynivalenol in the feed. This study assesses the effect of chronic consumption of zearalenone on reproduction in cycling mares fed >95% pure ZON (0, 2, or 8 mg/da; n = 7 mares/treatment) for three estrous cycles, followed by artificial insemination, through 16 days of pregnancy. Animals were on ZON treatment for between 70 and 121 days (average 84) depending on individual cycle patterns. ZON-induced changes in serum concentration of estradiol (E 2) and progesterone (P 4), and total estrogenicity were measured using RIAs and the E-screen assay, respectively. Effects on reproductive physiology and pregnancy were monitored by ultrasound and clinical parameters. No significant changes were found in reproductive hormone levels of E 2 , or P 4 for mares on ZON treatments compared to controls, although there was a significant (P < 0.01) increase in P 4 levels across Cycle number in High ZON (8 mg/da) treated mares. There was also an increasing trend in the interovulatory interval in the High ZON treatment group. The overall estrogenicity was similar across treatments and over time, not differing from controls or between ZON treatment groups. Adverse uterine and ovarian effects were also not observed, but pregnancy rates were mixed with only 4 of 7 mares on Low ZON becoming pregnant, and only 3 maintaining pregnancy and fetal heartbeat by Day 30, compared to 5 of 6 control mares and all 7 mares on High ZON. Because reproductive efficiency and hormone concentrations are highly variable across individuals, this study did not demonstrate that ZON at 2 or 8 mg/da was detrimental to mares' reproduction. Yet, inferring that ZON treatments were completely without effect is also not appropriate, as the absence of measurable significant differences could be attributed to the limited sample size. Most importantly, there were no extreme signs of toxicology, in contrast to previous reports when ZON was fed at these "doses."

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Section: Discussionsupporting

confidence: 77%

Reproductive Performance of Mares Fed Dietary Zearalenone

et al. 2019

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“…In the present study, serum P4 concentrations greater than 10 nmol/L on Day 15 were considered to indicate a prolonged luteal phase in the mares of IUD group (46.7%), while P4 concentrations less than 6 nmol/L were considered to be representative of mares having a normal luteal phase even when treated with the IUD (53.3%). Reports from earlier studies, however, indicate that some mares with prolonged diestrus have relatively lesser P4 concentrations at the time of the expected luteolysis (Rivera del Alamo et al, 2008;Ginther et al, 2015Ginther et al, , 2016. These decreased P4 concentrations occurred concurrent with the day when there was the maximal diameter of a dominant follicle (Santos et al, 2015a) or may have resulted as a consequence of partial luteolysis (Ginther et al, 2016).…”

Section: Discussionmentioning

confidence: 92%

“…The P4 concentrations were decreasing during this time period and were somewhat less than those of the mares that were COX-2 negative in this group. Another explanation could be fluctuating P4 concentrations at the time of expected luteolysis, since P4 concentrations decrease in both IUD-induced and idiopathic luteal persistence (Rivera del Alamo et al, 2008;Ginther et al, 2015Ginther et al, , 2016. Partial luteolysis (Ginther et al, 2016) could occur as a result of increased COX-2.…”

Section: Discussionmentioning

confidence: 99%

Cyclooxygenase-2 is inhibited in prolonged luteal maintenance induced by intrauterine devices in mares

Álamo

Reilas

Galvão

et al. 2018

Animal Reproduction Science

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Treatment with intrauterine devices (IUD) prolongs luteal phases in mares, but the mechanism for this has not been fully elucidated. The aims of the present study were to examine how IUDs affect the uterus to induce longer luteal phases, particularly the role of cyclooxygenase-2 (COX-2) in the maintenance of the corpus luteum (CL). Twentyseven reproductively normal mares were included: 12 were inseminated (AI), and 15 were fitted with IUDs. Blood samples for progesterone were obtained on Days 0, 3, 5, 7, 9, 11, 13, 14, and 15 (relative to day of ovulation). The groups were further divided into non-pregnant (AI-N, n = 4), pregnant (AI-P, n = 8), normal (IUD-N, n = 8) and prolonged luteal phase (IUD-P, n = 7) based on ultrasonic examinations and serum progesterone concentrations on Days 14 and 15. Blood sampling to quantify the PGF2 metabolite (PGFM) was performed through a catheter hourly from 15:00 to 20:00 hour on Day 14, and from 6:00 until 13:00 hour on Day 15. On Day 15, a low-volume uterine lavage followed by an endometrial biopsy was performed. Estradiol concentration in the Day 15 serum and lavage fluid was determined, while the abundance of COX-2 was evaluated in the biopsy specimens using western blotting (WB) and immunohistochemistry (IHC). All pregnant mares were negative for COX-2 in IHC samples and 5 of 8 were negative in WB samples while all mares of the IUD-N group were positive for COX-2. Of the seven mares in the IUD-P group, five and four were negative for COX-2 with the IHC and WB samples, respectively. The results from this study indicate that IUDs, when effective, suppress COX-2, leading to the inhibition of PGF2 release and maintenance of CL.

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“…The corpora lutea that failed to regress at the normal time were considered pathologically persistent CL. The CL persisted for 2-3 months, and the mare did not show estrous behavior [7]. Of the 12 mares diagnosed with PCL, one was not in the PCL category because of a P4 concentration of 0.5 ng/mL (day 0).…”

Section: Discussionmentioning

confidence: 98%

“…To induce luteolysis, a single dose of PGF2α intramuscular treatment is routinely used permitting a subsequent return to the estrus of mares [6]. However, by intramuscular administration, the migration of PGF2α from the injection site to the ovaries of a mare is through the whole body (systemically) [7], which requires a high dose. There has not been reported use of intrauterine PGF2α for estrus induction to restore fertility in racing mares with PCL.…”

Section: Introductionmentioning

confidence: 99%

Fertility restoration of racing mare with persistent corpus luteum

et al. 2021

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Background and Aim: Persistent corpus luteum (PCL) causes anestrus in mares. This study aimed to determine the effect of intrauterine prostaglandin F2α (PGF2α) treatment on PCL of racing mares to restore fertility. Materials and Methods: Twelve racing mares suspected with PCL were diagnosed using transrectal palpation and confirmed by serum progesterone (P4) concentration measurement. PGF2α was infused intrauterine, followed by serum collection at 24, 48, and 72 h after. Estrous symptoms were monitored, and mating was conducted on day 3 of estrus with an earlier injection of 8.4 μg gonadotropin-releasing hormone twice a day. Transrectal palpation was performed on days 21-30 to observe the corpus luteum. Pregnancy diagnosis was performed rectally on 40-45 days post-mating and confirmed using Doppler ultrasound scanning. Results: Eleven of the 12 mares had PCL. There was a dramatic reduction in the P4 concentration following PGF2α treatment of mares with PCL. All mares exhibited estrus 2.6±0.55 days post-treatment with a P4 concentration of 0.12±0.12 ng/mL. Rectal palpation and P4 concentration on 21-30 days after estrous onset showed that all mares were ovulating. The evaluation of P4 concentration on days 40-45 post-mating showed that all mares were still in the luteal phase. However, the pregnancy rate was only 54.5% based on rectal palpation and Doppler ultrasound scanning. Conclusion: Treatment of PCL in racing mares with an intrauterine infusion of PGF2α restored the estrous cycle and induced ovulation and pregnancy.

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Defective secretion of Prostaglandin F2α during development of idiopathic persistent corpus luteum in mares

Cited by 8 publications

References 18 publications

Reproductive Performance of Mares Fed Dietary Zearalenone

Reproductive Performance of Mares Fed Dietary Zearalenone

Cyclooxygenase-2 is inhibited in prolonged luteal maintenance induced by intrauterine devices in mares

Fertility restoration of racing mare with persistent corpus luteum

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