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Klinische, endokrinologische, sonographische und lichtmikroskopische Untersuchungen zur Physiologie und Pathophysiologie der Trächtigkeit des Hundes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Politt, E. |
| Copyright Year | 2004 |
| Abstract | Administering antigestagenic or luteolytic substances to the mismated bitch frequently results in death and resorption of the majority of the conceptus but not of all, if the treatment is not repeated or prolonged. Only little is known about the local processes taking place in spontaneous and induced embryonic/fetal death in canine pregnancy. Morphological studies are still missing. In an orientation study eight Beagle bitches were examined in two consecutive pregnancies. Two bitches (K I, K II; group K) served as controls, while three bitches (A I, A II, A III; group A) were administered Aglepristone (10 mg/kg s.c.) at day 24 and 25 after ovulation (p.ov.) and three bitches (C I, C II ,C III; group C) received cloprostenol (1µg/kg s.c. at day 24 and 27 p.ov.) in combination with the dopamine-agonist cabergoline (5µg/kg p.o. from day 24 p.ov. to day 30 p.ov.). If the pregnancies were not terminated until day 36 (1st gestation) or until day 31 (2nd gestation) treatment were repeated until the last conceptus died or until ovariohysterectomy, respectively. As the bitch C II suffered from an endometritis after the 1st pregnancy she had to be replaced by bitch C III. Therefore, C III passed only the 2nd gestation. The ultrasonographic features of the conceptuses and the embryonic/fetal heart rate were examined every day using real-time ultrasonography. The perfusion of individual placental sites was measured every other day by Doppler ultrasonography until the last fetus died. Furthermore the concentrations of oesteradiol-17s (E2), progesterone (P4) and relaxin (RLX) were determined in peripheral blood serum. During the 2nd pregnancy the examinations were performed until ovariohysterectomy between day 30 and 34 after ovulation (p.ov.), when some of the fetuses were already dead. The control dogs were ovariohysterectomized at corresponding days. The hormone analysis revealed normal E2 concentrations in all bitches and physiological P4 and RLX patterns in the control group. In the control bitch K II two spontaneous resorptions occurred during the 1st (day 24 and 33 p.ov.) and three during the 2nd pregnancy (day 21, 24 and 28 p.ov.). Under Aglepristone treatment the peripheral P4 and RLX concentrations did not differ from those of the control group before pregnancies were definitely terminated. Thereafter both hormones showed a marked decline. Death of the first embryo occurred 2 to 4 days after the first aglepristone administration. Termination of the first pregnancies was completed between 15 and 17 days after the initial aglepristone injections. The cloprostenol/cabergoline treated dogs showed a sharp drop of P4 concentrations one day after the start of medication and a further decrease during the treatment period. However, P4 levels were not suppressed to < 2 ng/ml by the basal medication. During the 2nd pregnancy P4 concentrations of < 2 ng/kg were measured after repeated medication in both dogs at the day of ovariohysterectomy. The decrease of P4 was followed by death of the first embryo/fetus between day 3 and 8 of treatment. In both bitches the first pregnancy was terminated 13 days after start of treatment (day 37 p.ov.). After death of the last conceptus the peripheral RLX concentrations dropped sharply in the last third of pregnancy. Average embryonic heart rate in the pretreatment period (days 21 to 24 p.ov.) was 192 b.p.m. (beats per minute) in all groups. In mid-pregnancy (day 29 to 31 p.ov) the mean embryonic/fetal heart rate reached a plateau of about 234 b.p.m. without showing any influence of either medication. In three fetuses a dramatic reduction of the heart rate was detected maximally 2 hours before the death. In the control group a reduction of the mean heart rate to 212 b.p.m. was noted in the prepartum period (day 61 p.ov.). The blood flow velocities in the uterine arteries measured in the neighbourhood of the intact placental sites increased gradually throughout physiological pregnancy in both bitches of group K. The aglepristone treatment led to a significant decrease of the time average maximum velocity (TAMAX) at the days 25/27 p.ov. and of the S/D-ratio at days 29/31 p.ov.. The pulsatility index, the resistance index and the A/B-ratio in the bitches in the group C was significantly lower than in the control group before (at days 21/23 p.ov.) and after the start of cloprostenol/cabergoline treatment (at days 25/27 p.ov.). The S/D-ratio was also significantly decreased at days 25/27 p.ov. and at days 29/31 p.ov. a significant decrease of all blood flow velocities (SPV, DPV, EDV, TAMAX) was observed. In the placental sites of the intact conceptuses of groups A and C no macroscopic or microscopic signs of placental distress and no sings of the treatment mechanisms could be identified. No morphological differences were observed between the spontaneous (bitch K II) and induced resorptions (group A and C). After embryonic/fetal death the placental labyrinth was completely disintegrated. Signs of resorption like an increased macrophage infiltration in the maternal stroma were absent. The vaginal discharge observed in all bitches of groups A and C in the 1st pregnancy macroscopically corresponded to the fluid masses found in the resorption sites after ovariohysterectomy. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://elib.tiho-hannover.de/servlets/MCRFileNodeServlet/etd_derivate_00002364/politte_ws04.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
