Kisspeptin-10 and the G protein-coupled receptor 54 are differentially expressed in the canine pregnant uterus and trophoblast cells.

Uterine tissue was collected from bitches after ovariohysterectomy at different times after ovulation. Samples were assigned to four groups: metestrous non-pregnant, day 10-12, n = 4; pre-implantation, day 10-12, n = 9; post-implantation, day 18-25, n = 13; mid-gestation, day 30-40, n = 7. RT-qPCR detection was performed for kiss1 and the G protein-coupled receptor 54 (GPR54, specific receptor for kisspeptin). In addition, immunohistochemistry was performed for detection of kisspeptin-10 (KP-10), GPR54, as well as pan-cytokeratin and vimentin. The latter two were included to differentiate the different placental cell types. The percentage of positive stained cells was evaluated, and an immunoreactivity score (IRS) was obtained by multiplying the labelling intensity score (0-3) with the percentage of immunolabelled cells (range: 0-300). In non-pregnant and pre-implantation tissues, gene expression was highly variable for kiss1 and GPR54. Expression of GPR54 was higher before embryo adhesion than during post-implantation and mid-gestation (p < .05), whereas there was no difference found between groups for kiss1. Except during the pre-implantation period, KP-10 expression was higher in the non-pregnant uterus compared to all gestational periods investigated, indicating a pregnancy-related downregulation. In the pre-implantation period, KP-10 was present in larger vessels only, whereas the presence of GPR54 in vessels was found in all samples, with most labelling in the post-implantation period. KP-10 was present in superficial uterine glands, GPR54 in superficial and deep uterine glands of the post-implantation uterus. In myocytes, the highest staining for KP-10 was seen in the non-pregnant uterus, whereas the highest staining for GPR54 was seen in post-implantation and mid-gestation. Syncytiotrophoblast cells stained for both KP-10 and GPR54 in post-implantation and mid-gestation, with maximum intensity for GPR54 in the latter. We conclude that KP-10 and GPR54 are expressed in the canine uterus and trophoblast cells. However, during pregnancy, expression of both proteins seems to be differentially regulated.

The effects of aglepristone alone and in combination with cloprostenol on hormonal values during termination of mid-term pregnancy in bitches.

This study was designed to assess endocrine changes associated with termination of mid-term pregnancy after use of two different protocols. For this purpose we compared the effects of aglepristone (AGL) alone and in combination with cloprostenol (CLO) on serum concentrations of progesterone (P4), estradiol (E2) and relaxin (RLN) measured at short-term intervals during the abortion period in bitches. Fourteen pregnant bitches between day 25 and 32 of gestation were used in the study. In the AGL group (n=7), aglepristone was administered solely (10mg/kg body weight (BW), subcutaneously, once daily on two consecutive days) whereas in the AGL-CLO group (n=7), aglepristone (dosage as in AGL group) and cloprostenol (1µg/kg BW, subcutaneously, same with aglepristone) were combined. All pregnancies were successfully terminated 5.2±1.6 days after initiation of treatments, which was significant in both groups (P>0.05). At the time of the start of abortion (SA) and the end of abortion (EA), the mean P4 concentrations were 26.6±7.3 and 12.0±6.4ng/ml in AGL group, and 2.7±0.7 and 0.9±0.1ng/ml, in AGL-CLO group, respectively (P<0.01). Serum E2 concentrations were significantly higher (P<0.05) in AGL group at 42, 48, 54h and SA after initiation of treatment. In the AGL-CLO group, serum RLN concentrations did not significantly change from the initiation of treatment to EA (P>0.05). However, markedly higher RLN concentrations (P<0.05) were observed in the AGL group at 48h (1.5±0.7ng/ml) and at SA (1.6±0.5ng/ml). The results of the present study indicate that changes in the hormonal concentrations affect the mechanism of abortion in different ways. Further in depth studies investigating changes in the expression of hormone receptors inside the ovary, endometrium and placenta might be helpful to our understanding of the endocrinological differences observed in this study.

The intravaginal application of misoprostol improves induction of abortion with aglepristone.

The aim of the present study was to compare the clinical and endocrinological effects of four different treatments for the induction of abortion in bitches. For this purpose, 28 pregnant bitches between days 25 and 35 of gestation, were randomly assigned to four groups. In group I (n = 7), only aglepristone (AGL, 10mg/kg bw, two injections 24 h apart, s.c.) was administered. In group II (n = 7), AGL (as in group I), cabergolin (CAB, 5 µg/kg, daily p.o., until completion of abortion) and misoprostol (MIS, 200 µg for bitches with ≤ 20 kg bw, 400 µg for bitches with > 20 kg bw, daily intravaginally, until completion of abortion) were administered. In group III (n = 7), AGL (as in group I) and MIS (as in group II) were administered. In group IV (n = 7) AGL, (as in group I) and cloprostenol (CLO, 1µg/kg bw, s.c., two injections 24 h apart with the AGL injections) were combined. In all groups, bitches were examined daily, clinically and ultrasonographically to monitor resorptions/abortions. To measure serum progesterone (P4) and total estrogen (TE) concentrations, blood samples were collected in all groups immediately after the first AGL administration and every other day until completion of abortion. No statistical differences were found between groups concerning the duration until completion of abortion following treatment (n.s.); however, in Group III, 6 d after the start of treatment all pregnancies were terminated whereas in Group I, II and IV, only 57.1% (4/7), 85.7 % (6/7) and 42.8 % (3/7) of pregnancies were terminated. In the latter groups, all pregnancies were terminated between days 8 and 10 after the start of treatment. In Group IV, P4 concentrations on days two and one before the beginning of abortion and the day the abortion started was significantly lower than in the other groups (P < 0.01). No statistical differences were found between groups for TE concentrations (P > 0.05). In Groups I, II and III, no severe side effects occurred. Severe vomiting after each treatment and until the end of abortion was observed in Group IV only. In conclusion, only when a combination of AGL and MIS was used abortion was completed within 6 d in all bitches whereas the additional use of CAB did not improve the treatment.

Uterine progesterone receptor and leukaemia inhibitory factor mRNA expression in canine pregnancy.

The study investigated the expression of genes for progesterone receptor (PR) and for the cytokine leukaemia inhibitory factor (LIF) in the uterine tube and uterine horn tissues from pregnant and non-pregnant bitches. The aim was to study whether a relation existed between the likely biological effectiveness of progesterone (P(4)) and the change in the uterine expression of LIF mRNA during pregnancy, as has been described in primates. For this purpose, 20 pregnant bitches were ovariohysterectomized after being allotted to three groups according to gestational age (pre-implantation: days 10 to 12, n = 7; peri-implantation: days 18 to 25, n = 7; post-placentation: days 28 to 45, n = 7). Tissue samples were obtained from the uterine tubes, one uterine horn (including placentation sites and interplacental sites in bitches that had already implanted) and the corpus uteri, stored at -80 degrees C, and then analysed by qualitative and quantitative PCR for PR and LIF mRNA expression. From the pre-implantation to the placentation stage, a decrease in the relative expression of PR mRNA in uterine tissue was obvious and significant when expressed relative to beta-actin (11.2 +/- 6.8 vs 2.7 +/- 1.9; p < 0.05). However, over the same period, the relative expression of LIF mRNA increased (10.1 +/- 16.1 vs 50.0 +/- 32.3; p < 0.05). In addition, PR mRNA went from being detectable to no longer detectable in the uterine tube, and no longer detectable in interplacental-site uterine tissue. We conclude that LIF is important for the establishment of canine pregnancy; that decreased uterine PR mRNA expression may contribute to the increase in uterine LIF mRNA; and, that the ability of the embryo to preserve PR mRNA expression at implantation and placentation sites while expression is lost in the remainder of the uterus represent an effect important to the establishment and maintenance of pregnancy. We additionally propose that canine embryo secretory proteins have a regulatory effect on both PR and LIF before as well as at and after implantation.

Induction of abortion with aglepristone significantly changed the expression of progesterone and estrogen receptors in canine endometrial stromal cells.

In the present study, resorption/abortion was induced between days 25 and 45 of gestation with aglepristone (group IRA, n=10). The aim was to observe the change in the distribution of progesterone (PR) and estrogen receptors (ER), in comparison to a group of spontaneous resorptions/abortions (group SRA, n=5), and a further group of normal healthy pregnant animals, ovariohysterectomized between days 25 and 45 of gestation (controls, n=7). The receptors were assessed by means of immunohistochemistry (IHC) and RT-PCR, at the placental and interplacental sites of the uterine horn as well as in the corpus uteri. Significant differences were observed between the controls on one side and the groups of resorption/abortion on the other side. The total scores of the progesterone receptors (TPR) in the placental and interplacental part of the uterine horn, was significantly lower in the endometrial stromal cells (ESC) of the control group than in those of the SRA- and IRA-group, respectively (placenta: 5.8 vs. 6.5 and 6.7, p<0.01; interplacental sites: 5.6 vs. 6.6 and 6.6, p<0.05). In contrary, the total scores of the estrogen receptors (TER) at interplacental sites and the corpus uteri, respectively, was significantly higher in the myometrial smooth muscle cells (MSMC) and the ESC (p<0.05) of the controls. We therefore conclude, that the here observed differences between groups point to an up-regulation of TPR- and a down-regulation of TER-scores in endometrial stromal cells at different uterine sites during resorption/abortion, which indicates a special role of these cells.