Division of Veterinary Surgery, School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK.
Vet J. 2013 Aug;197(2):205-10. doi: 10.1016/j.tvjl.2013.02.015. Epub 2013 Jun 14.
The aim of this study was to measure uterine artery blood velocity daily using Doppler ultrasonography in 10 young and 10 older clinically normal bitches throughout oestrus. Typical arterial waveforms identified in young bitches were characterised by a systolic peak and subsequent flow throughout diastole, whereas in older bitches, flow was sometimes absent in diastole. For 3 days immediately prior to ovulation, at the time of declining plasma oestrogen and increasing progesterone concentrations, resistance index (RI) increased, principally associated with decreased diastolic velocity; in some bitches there was absent late diastolic flow during this time. In older bitches, the waveform appearance was more variable, with absent late and early diastolic flow observed in some cases. Mean RI was higher throughout oestrus for older bitches compared with young bitches, although both groups had a similar 3-day duration increase before ovulation. Nine of the young bitches and five of the older bitches became pregnant; litter size was smaller for the older bitches. Non-pregnant bitches: (1) were significantly older; (2) had fewer waveforms with continuous diastolic flow 2 days before ovulation; (3) had lower end diastolic velocity, higher RI and fewer waveforms with continuous diastolic flow 2 days after ovulation, and (4) had lower plasma progesterone concentrations 5 days after ovulation. These are the first detailed observations of uterine artery blood velocity and waveform appearance throughout oestrus in bitches, and this is the first description of a link between impaired diastolic flow and reduced fertility. Assessment of uterine artery velocity could be useful to promote understanding of physiological mechanisms and could also become an important tool to assess potential infertility.
本研究的目的是在发情期内每天使用多普勒超声对 10 只年轻犬和 10 只老年犬的子宫动脉血流速度进行测量。在年轻犬中，典型的动脉波形特征是收缩期峰值和随后的舒张期血流，而在老年犬中，舒张期血流有时不存在。在排卵前的 3 天内，即血浆雌激素下降和孕酮浓度增加时，阻力指数（RI）增加，主要与舒张末期速度降低有关；在一些犬中，此时舒张末期无血流。在老年犬中，波形外观更为多变，在某些情况下，舒张末期和早期舒张期无血流。与年轻犬相比，老年犬在发情期的平均 RI 较高，尽管两组在排卵前都有相似的 3 天持续增加。9 只年轻犬和 5 只老年犬怀孕；老年犬的产仔数较少。未怀孕的犬：（1）年龄显著较大；（2）在排卵前 2 天，具有连续舒张期血流的波形更少；（3）在排卵后 2 天，舒张末期速度更低，RI 更高，具有连续舒张期血流的波形更少，以及（4）在排卵后 5 天，血浆孕酮浓度更低。这些是发情期犬子宫动脉血流速度和波形外观的首次详细观察，也是首次描述舒张期血流受损与生育力降低之间的联系。评估子宫动脉速度可能有助于促进对生理机制的理解，也可能成为评估潜在不孕的重要工具。
