Chatdarong Kaywalee, Lohachit Chainarong, Kiartmanakul Soonthorn, Axnér Eva, Forsberg Catharina Linde
Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.
Theriogenology. 2006 Sep 1;66(4):804-10. doi: 10.1016/j.theriogenology.2006.01.053. Epub 2006 Mar 9.
The cervix functions as a barrier to spermatozoa. Vaginal artificial insemination in cats is, therefore, likely to be successful only at the period of estrus when the cervix is open. This study aimed to define the period of cervical patency in cats in both non-ovulatory and ovulatory estrus cycles. A total of 15 reproductive cycles were studied in six cats during the estrous stage. Cervical patency was monitored with the cats under sedation, by infusing 2 mL of Iohexol contrast medium via a 3.5 French tomcat catheter into the cranial vagina during estrus. Day one of estrus was defined as the first day the cats showed estrous behavior. Non-ovulatory cycles were characterized by a serum progesterone concentration on days 11-15 that was below 5 nmol/L and a normal interestrus interval of 7-14 days. Ovulatory cycles were characterized by a serum progesterone concentration on days 11-15 that was above 5 nmol/L and an interestrus interval that exceeded 30 days. The cervix was considered to be open when the contrast medium was seen to enter the uterus, and to be closed when the contrast medium remained in the vagina. Blood samples were collected at each examination and were assayed for estradiol-17beta and progesterone concentrations. The cervix was open on the first day of standing estrus at a mean estradiol-17beta serum concentration of 87.4+/-21.8 pmol/L (range 14 to >or=180 pmol/L) and closed at an estradiol concentration of 47.1+/-12.4 pmol/L (range 4 to >or=180 pmol/L). In the ovulatory cycles the cervix was closed at a progesterone concentration of 9.8+/-4.4 nmol/L (range 0.6-28.4 nmol/L). There was no difference in the duration of cervical patency in non-ovulatory and ovulatory cycles (5.5+/-1.2 days and 5.2+/-0.5 days, respectively) (p>0.05). The higher overall mean concentrations of estradiol-17beta seen in the ovulatory cycles than in the non-ovulatory cycles, indicate that a high level of estradiol is necessary for induction of ovulation. Ovulation in 60% of unmated females in this study indicates that the techniques used for evaluation of cyclus stage and cervical opening have the potential to induce ovulation in the cat. This study demonstrates that cervical patency is not influenced by the occurrence of ovulation, but is due to individual variations between cats.
子宫颈起到阻挡精子的作用。因此，猫的阴道人工授精可能仅在发情期子宫颈开放时才能成功。本研究旨在确定猫在非排卵性和排卵性发情周期中子宫颈开放的时期。在发情期对6只猫的总共15个生殖周期进行了研究。在镇静状态下对猫进行子宫颈通畅监测，在发情期通过一根3.5法式雄猫导管将2毫升碘海醇造影剂注入阴道上段。发情第一天定义为猫表现出发情行为的第一天。非排卵周期的特征是第11至15天血清孕酮浓度低于5 nmol/L，正常的乏情期为7至14天。排卵周期的特征是第11至15天血清孕酮浓度高于5 nmol/L，乏情期超过30天。当看到造影剂进入子宫时，子宫颈被认为是开放的；当造影剂留在阴道内时，子宫颈被认为是闭合的。每次检查时采集血样并测定雌二醇-17β和孕酮浓度。站立发情第一天时子宫颈开放，此时血清雌二醇-17β平均浓度为87.4±21.8 pmol/L（范围14至≥180 pmol/L），当雌二醇浓度为47.1±12.4 pmol/L（范围4至≥180 pmol/L）时子宫颈闭合。在排卵周期中，当孕酮浓度为9.8±4.4 nmol/L（范围0.6 - 28.4 nmol/L）时子宫颈闭合。非排卵周期和排卵周期中子宫颈开放的持续时间无差异（分别为5.5±1.2天和5.2±0.5天）（p>0.05）。排卵周期中观察到的雌二醇-17β总体平均浓度高于非排卵周期，这表明高水平的雌二醇对于诱导排卵是必要的。本研究中60%未交配雌性出现排卵，表明用于评估发情周期阶段和子宫颈开放的技术有可能诱导猫排卵。本研究表明，子宫颈通畅不受排卵发生的影响，而是由于猫个体之间的差异。
