Doppler sonography of the uterine and ovarian arteries during a superovulatory program in horses.
Abstract: The aim of the present study was to investigate the effects of a gonadotropin treatment to induce superovulation on ovarian and uterine blood flow and its relationship with steroid hormone levels and ovarian response in mares, using color Doppler sonography. Each of six mares were examined sonographically in five cycles for 3 d (t1 to t3) during the follicular development phase (FDP) beginning at a follicle size of ≥ 22 mm, and for 4 d (D-4 to D-1; D0 = Ovulation) in the preovulatory phase (POP). After each examination, total estrogens (E(tot)) and progesterone (P(4)) levels were determined in peripheral plasma. Cycles 1, 3, and 5 (c(1), c3, c5) were unstimulated cycles (USC); in c2 and c4, the mares were stimulated (SC) with eFSH and inseminated when in estrus at 12 and 24 h after hCG administration. Embryo recovery was performed 6.5 d post ovulation. Cycle 5 c5 was an unstimulated cycle with hCG treatment, insemination, and embryo recovery. Ovarian and uterine blood flow was quantified by the blood flow volume (BFV) and the pulsatility index (PI) in ovarian and uterine arteries. The mean number of ovulations and developing CL was 1.3 ± 0.4 in USC and 4.4 ± 3.1 in stimulated cycles (SC) with no difference (P ≥ 0.05) between the ovaries within mares. No difference (P > 0.05) was observed in utBFV and utPI during FDP between USC and SC, but during POP, utPI was lower (P < 0.05) and utBFV higher (P < 0.001) in SC than USC. The ovBFV was higher (P < 0.01) and ovPI lower (P < 0.05) in SC compared to USC. All uterine and ovarian blood flow parameters were related to the number of developing follicles in SC. Parameters utPI (r = -0.67; P < 0.001) and ovPI (r = -0.53; P < 0.001) were negatively correlated with the number of ovulations on t3, and with the number of collected embryos on t3 (utPI: r = -0.81; P < 0.001), D-4 (utPI: r = -0.64; P < 0.0001), and D-1 (ovPI: r = -0.41; P 0.05), but E(tot) concentrations (D-4: r = 0.790; D3: r = 0.639; P < 0.001; D-1: r = 0.48; P < 0.001) and ovBFV from D-4 to D-1 (r = 0.64; P < 0.001) in SC were. The results of the present study show that in mares treatment with gonadotropins to induce superovulation is associated with a marked increase in uterine and ovarian perfusion, concurrent with the development of multiple follicles and an increase in E(tot) levels. The increased blood flow seems to be related to the effectiveness of ovarian response to stimulation.
Copyright © 2012 Elsevier Inc. All rights reserved.
Publication Date: 2011-12-21 PubMed ID: 22196623DOI: 10.1016/j.theriogenology.2011.11.005Google Scholar: Lookup
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Summary
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This study investigates how treatment with gonadotropins, to stimulate superovulation, affects the ovarian and uterine blood flow in horses, its relationship with steroid hormone levels, and the response of the ovary to the treatment. Using color Doppler sonography, it was discovered that the treatment causes a significant increase in uterine and ovarian perfusion, which is concurrent with the development of multiple follicles and an increase in estrogen levels. This increased blood flow seems to be related to how effectively the ovaries respond to the stimulation.
Study Methodology
- The study observed six mares over five cycles and examined them sonographically for 3 days (from t1 to t3) during the follicular development phase, and for 4 days in the preovulatory phase. These examinations started when a follicle size of ≥ 22 mm was observed.
- Following each examination, the levels of total estrogens and progesterone in the peripheral plasma were determined.
- The cycles alternated, such that the 1st, 3rd and 5th cycles were unstimulated, while the 2nd and 4th cycles were stimulated using eFSH.
- The mares were inseminated when in estrus at 12 and 24 hours after hCG administration. Embryo recovery was carried out 6.5 days post ovulation.
- Ovarian and uterine blood flow were quantified by observing the blood flow volume and the pulsatility index in their respective arteries.
Results from Study
- The mean number of ovulations and developing Corpus Luteum (CL) was 1.3 ± 0.4 in unstimulated cycles and 4.4 ± 3.1 in stimulated cycles with no difference between the ovaries within mares.
- No difference was observed in the uterine blood flow volume and pulsatility index during the follicular development phase between the unstimulated and stimulated cycles.
- However, during the preovulatory phase, the pulsatility index was lower and blood flow volume was higher in stimulated cycles than in unstimulated cycles.
- All uterine and ovarian blood flow parameters were related to the number of developing follicles in the stimulated cycles.
- The pulsatility index in both the uterine and ovarian arteries showed a negative correlation with the number of ovulations on t3, and with the number of collected embryos on different days.
- Progesterone levels were not positively correlated with the uterine blood flow volume.
- However, the estrogen levels and ovarian blood flow volume in the stimulated cycles showed a positive correlation.
Conclusion
The research found that treatment with gonadotropins to induce superovulation in mares resulted in a significant increase in uterine and ovarian blood flow. This increased blood flow was concurrent with the development of multiple follicles and an increase in estrogen levels, indicating a correlation between gonadotropin treatment, increased perfusion and steroid hormone levels. The results suggest that this increased blood flow may be related to the effectiveness of the ovarian response following stimulation, ultimately improving the outcome of superovulation.
Cite This Article
APA
Witt MC, Bollwein H, Probst J, Baackmann C, Squires EL, Sieme H.
(2011).
Doppler sonography of the uterine and ovarian arteries during a superovulatory program in horses.
Theriogenology, 77(7), 1406-1414.
https://doi.org/10.1016/j.theriogenology.2011.11.005 Publication
Researcher Affiliations
- Clinic for Horses, Unit for Reproductive Medicine, University of Veterinary, Medicine Hanover Foundation, Buenteweg 9, 30559 Hanover, Germany. mellikoellmann@web.de
MeSH Terms
- Animals
- Female
- Follicle Stimulating Hormone / pharmacology
- Gonadotropins, Equine / pharmacology
- Horses / anatomy & histology
- Ovarian Follicle / blood supply
- Ovarian Follicle / diagnostic imaging
- Ovarian Follicle / drug effects
- Ovary / blood supply
- Ovary / diagnostic imaging
- Ovary / drug effects
- Ovulation Induction / methods
- Ovulation Induction / veterinary
- Regional Blood Flow / drug effects
- Ultrasonography, Doppler / veterinary
- Uterine Artery / diagnostic imaging
- Uterine Artery / drug effects
- Uterus / blood supply
- Uterus / diagnostic imaging
- Uterus / drug effects
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