Uterine and ovarian blood flow during the estrous cycle in mares.
Abstract: Uterine and ovarian blood flow was investigated in four mares during two consecutive estrous cycles using transrectal color Doppler sonography. The uterine and ovarian arteries of both sides were scanned to obtain waves of blood flow velocity. The pulsatility index (PI) reflected blood flow. There were significant time trends in PI values of all uterine and ovarian blood vessels during the estrous cycle (P < 0.05). PI values did not differ between the uterine arteries ipsi- and contralateral to the corpus luteum or the ovulatory follicle. PI values of the uterine arteries showed a wave shaped profile throughout the estrous cycle. The highest PI values occurred on Days 0 and 1 (Day 0 = ovulation) and around Day 11, and the lowest PI values were measured around Days 5 and -2 of the estrous cycle. During diestrus (Days 0-15) PI values of the ovarian artery ipsilateral to the corpus luteum were significantly lower than PI values of the contralateral ovarian artery (P 0.05) in resistance to ovarian blood flow occurred between sides during estrus (Days -6 to -1). In this cycle stage PI values decreased in both ovarian vessels (P < 0.05). During diestrus, high PI values of the ovarian artery ipsilateral to the corpus luteum were measured between Days 0 and 2, followed by a decline until Day 6 (P < 0.05). From this time on, the resistance to blood flow increased continuously until Day 15 (P < 0.05). The cyclic blood flow pattern in the contralateral ovarian artery was similar to that in the uterine arteries (r = 0.68; P 0.05) during diestrus. During estrus, there was a negative relationship between growth of the diameter of the ovulatory follicle and changes in PI values of the dominant ovarian artery (r = -0.41; P < 0.05). PI values of the uterine arteries and of the ovarian artery ipsilateral to the ovulatory follicle were negatively related to estrogen (E) levels in plasma during estrus (uterine arteries: r = -0.21; P < 0.05; dominant ovarian artery: r = -0.35; P < 0.05). In diestrus, PI values of the dominant ovarian artery were negatively related to plasma progesterone levels (r = -0.38; P 0.05). The findings of this study show that there are characteristic changes in blood supply of the uterus and the ovaries throughout the equine estrous cycle. There are negative correlations between resistance to blood flow in the uterine and ovarian arteries and the plasma estrogen levels during estrus. In diestrus, there is a negative relationship between the resistance to ovarian blood flow and the progesterone levels.
Publication Date: 2002-06-18 PubMed ID: 12066871DOI: 10.1016/s0093-691x(02)00703-3Google Scholar: Lookup
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Summary
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This research investigates changes in blood flow to the uterus and ovaries in mares during their estrous cycle. The research shows that blood flow changes are characteristic and correlate with estrogen and progesterone levels.
Overview of the Study
- The study focused on the analysis of uterine and ovarian blood flow in female horses (mares) during two consecutive estrous cycles.
- The estrous cycle refers to the recurring physiological changes that are induced by reproductive hormones in most mammalian therian females.
- This involved conducting a transrectal color Doppler sonography, a kind of diagnostic imaging technique that uses sound waves to investigate the flow of blood in the vessels.
- The aim was to understand how this blood flow reflected the pulsatility index (PI) – a measure that describes the variation in blood velocity within a single cycle of oscillation.
Key Findings
- There were significant changes in the PI values of all uterine and ovarian blood vessels during the estrous cycle.
- The PI values did not differ between the uterine arteries on the same side as the corpus luteum (a structure that develops in an ovary after an ovum has been discharged) and the ovulatory follicle, and those on the opposite side.
- The PI values of the uterine arteries showed a wave-shaped profile throughout the estrous cycle. The highest PI values occurred on Days 0 and 1 (Day 0 being ovulation day) and around Day 11, with the lowest PI values noted around Days 5 and -2 of the estrous cycle.
- During diestrus (part of the cycle when the animal returns to a sexually quiescent stage), the PI values of the ovarian artery on the side of the corpus luteum were much lower than those on the opposite side.
- No significant differences in resistance to ovarian blood flow occurred between sides during the estrus phase (the period when the female is sexually receptive).
- There was no correlation found between the diameter of the corpus luteum and the PI values of the ovarian artery on the same side during diestrus.
Correlation with Hormone Levels
- During estrus, there was a negative correlation between the increasing diameter of the ovulatory follicle and changes in PI values of the dominant ovarian artery.
- The PI values of the uterine arteries and of the ovarian artery on the side of the ovulatory follicle were negatively related to estrogen levels in the plasma during estrus.
- In diestrus, PI values of the dominant ovarian artery were negatively related to plasma progesterone levels, but no significant correlation was found with the PI values of the uterine arteries.
Significance of the Findings
- The results indicate that there are characteristic changes in the blood supply to the uterus and the ovaries throughout the equine estrous cycle.
- These changes in blood flow have important correlations with changes in plasma estrogen and progesterone levels at different stages of the estrous cycle.
- Understanding these physiological changes is crucial for the management of female horse health and reproduction.
Cite This Article
APA
Bollwei H, Weber F, Kolberg B, Stolla R.
(2002).
Uterine and ovarian blood flow during the estrous cycle in mares.
Theriogenology, 57(8), 2129-2138.
https://doi.org/10.1016/s0093-691x(02)00703-3 Publication
Researcher Affiliations
- Gynäkologische und Ambulatorische Tierklinik der Universität München, Germany. heinrich.bollwein@gyn.vetmed.uni-muenchen.de
MeSH Terms
- Animals
- Arteries / diagnostic imaging
- Blood Flow Velocity
- Diestrus
- Estrous Cycle / physiology
- Female
- Horses / physiology
- Ovarian Follicle / anatomy & histology
- Ovary / blood supply
- Ovulation
- Progesterone / blood
- Pulsatile Flow
- Ultrasonography, Doppler, Color
- Uterus / blood supply
- Vascular Resistance
Citations
This article has been cited 3 times.- Ortega-Ferrusola C, Gómez-Arrones V, Martín-Cano FE, Gil MC, Peña FJ, Gaitskell-Phillips G, Da Silva-Álvarez E. Advances in the ultrasound diagnosis in equine reproductive medicine: New approaches.. Reprod Domest Anim 2022 Oct;57 Suppl 5(Suppl 5):34-44.
- Da Silva-Álvarez E, Gómez-Arrones V, Martín-Cano FE, Gaitskell-Phillips G, Ortiz-Rodríguez JM, Carrasco JJ, Gil MC, Peña Vega FJ, Ortega Ferrusola C. Endometrial area of the blood flow as a marker of endometritis in equine.. Reprod Domest Anim 2022 Oct;57 Suppl 5(Suppl 5):98-102.
- Ratto MH, Urra F, Silva M. Laterality of Ovulation and Presence of the Embryo Do Not Affect Uterine Horn Blood Flow During the First Month of Gestation in Llamas.. Front Vet Sci 2020;7:598117.
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