Sheep estrous synchronization is mainly based on progestagen-impregnated sponges which could cause vaginitis. Several species of Lactobacillus used as probiotics are commonly used in the treatment or prevention of urogenital infections in humans. However, no studies have been performed to analyze the potential use of probiotics to prevent urogenital infections in sheep. A randomized controlled clinical trial was conducted with 21 one-year-old ewes to develop a model of probiotic infusion in vaginal sponges in order to study their influence in ewe’s vaginal microbiota, general health status, fertility and prolificity. Synchronization of estrus was based on intravaginal sponges for 14 days. Bacterial communities (Enterobacteriaceae and lactic acid bacteria) were highly fluctuating over time and between animals. The safety of probiotic infusion (mix of Lactobacillus spp. 60% L. crispatus, 20% L. brevis and 20% L. gasseri) in the vagina of healthy ewes was firstly confirmed. Neutrophils were observed in 80% (8/10) of the control ewes compared to 36% (4/11) of the ewes in the probiotic group 2 days after sponge removal (p = 0.056). Fertility in the control and probiotic groups was 60% (6/10) and 91% (10/11), respectively p = 0.097. These results suggest that Lactobacillus spp. infusion in the ewe’s vagina does not affect general health status or fertility.

Lactic acid bacteria (LAB) dominate human vaginal microbiota and inhibit pathogen proliferation. In other mammals, LAB do not dominate vaginal microbiota, however shifts of dominant microorganisms occur during ovarian cycle. The study objectives were to characterize equine vaginal microbiota in mares by culture-dependent and independent methods and to describe its variation in estrus and diestrus. Vaginal swabs from 8 healthy adult Arabian mares were obtained in estrus and diestrus. For culture-dependent processing, bacteria were isolated on Columbia blood agar (BA) and Man Rogosa Sharpe (MRS) agar. LAB comprised only 2% of total bacterial isolates and were not related to ovarian phases. For culture-independent processing, V3/V4 variable regions of the 16S ribosomal RNA gene were amplified and sequenced using Illumina Miseq. The diversity and composition of the vaginal microbiota did not change during the estrous cycle. Core equine vaginal microbiome consisted of Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria at the phylum level. At the genus level it was defined by Porphyromonas, Campylobacter, Arcanobacterium, Corynebacterium, Streptococcus, Fusobacterium, uncultured Kiritimatiaellae and Akkermansia. Lactobacillus comprised only 0.18% of the taxonomic composition in estrus and 0.37% in diestrus. No differences in the relative abundance of the most abundant phylum or genera were observed between estrus and diestrus samples.

The article summarizes the results of several studies, which highlight the relevance of prostaglandins E2 (PGE2) and F2 (PGF2a) during the ovulatory process in mares and their implication in the pathogenesis of luteinized unruptured follicles. Following the preovulatory luteinizing hormone (LH) surge, the two prostaglandins are synthesized in granulosa cells. They subsequently trigger a cascade of events that lead to ovulation. The exogenous administration of intrafollicular PGE2 and PGF2a can induce follicle rupture and ovulation within 12 h of injection, even in mares in early estrus, and before the beginning of the abrupt rise of the preovulatory LH surge. The systemic administration of a prostaglandin synthesis inhibitor (flunixin-meglumine) during the periovulatory period blocks ovulation and induces the development of luteinized unruptured follicles (LUFs). LUFs share similar ultrasonographic and hormonal characteristics with hemorragic anovulatory follicles (HAFs). The administration of intrafollicular PGE2 and PGF2a in mares treated with a prostaglandin synthesis inhibitor restores normal ovulation and allows oocyte release and fertilization. However, the systemic administration of prostaglandins does not appear to have any effect on hastening ovulation. Keywords: mare / reproduction /ovulation / LUF / PGE2 / PGF2a Citation: Cuervo-Arango J., Martínez-Boví R. (2016) The role of PGE2 and PGF2a in follicle wall rupture and their implications in the development and treatment of luteinized unruptured follicles. Pferdeheilkunde 32, 54-56

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The objectives were to determine: (i) whether intrafollicular administration of PGE2 and PGF2α to mares would hasten follicle collapse and (ii) the differences in reproductive hormone characteristics in mares with spontaneous and prostaglandin-induced follicle collapses. Six mares were followed for two oestrous cycles each: when the mares reached a follicle diameter of 30-35 mm and showed mild-to-moderate endometrial oedema, mares were administered a single 0.5 ml dose containing 500 μg PGE2 and 125 μg PGF2α (treatment cycle) or a placebo (0.5 ml of water for injection; control cycle) into the preovulatory follicle (Hour 0). Blood samples were collected, and serial ultrasound examinations were performed until follicle collapse. Treated mares showed follicle collapse significantly earlier (20.0 ± 5.9 h) than the control mares (72.0 ± 10.7 h). The LH, progesterone, total oestrogens and oestradiol concentrations did not differ between groups; however, the progesterone concentration increased more between 48 and 72 h after follicle injection in the treatment compared to the control cycles (P < 0.05). In conclusion, intrafollicular treatment with PGE2 and PGF2α hastened follicle collapse in mares without the simultaneous use of an inductor of ovulation; despite the early induction of follicle collapse, the profiles of LH and oestradiol were not altered. This study provides information on the role of prostaglandins (PGs) in the process of follicle wall rupture and collapse and suggests that this may happen even before the beginning of the sharp rise in circulating LH at the final stage of the ovulatory surge.

Summary:The article summarizes the results of several studies, which highlight the relevance of prostaglandins E2 (PGE2) and F2 (PGF2a) during the ovulatory process in mares and their implication in the pathogenesis of luteinized unruptured follicles. Following the preovulatory luteinizing hormone (LH) surge, the two prostaglandins are synthesized in granulosa cells. They subsequently trigger a cascade of events that lead to ovulation. The exogenous administration of intrafollicular PGE2 and PGF2a can induce follicle rupture and ovulation within 12 h of injection, even in mares in early estrus, and before the beginning of the abrupt rise of the preovulatory LH surge. The systemic administration of a prostaglandin synthesis inhibitor (flunixin-meglumine) during the periovulatory period blocks ovulation and induces the development of luteinized unruptured follicles (LUFs). LUFs share similar ultrasonographic and hormonal characteristics with hemorragic anovulatory follicles (HAFs). The administration of intrafollicular PGE2 and PGF2a in mares treated with a prostaglandin synthesis inhibitor restores normal ovulation and allows oocyte release and fertilization. However, the systemic administration of prostaglandins does not appear to have any effect on hastening ovulation.

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