Search

A new protocol with aglepristone to induce parturition in ewes with pregnancy toxemia has been reported in the present manuscript. Four experimental groups were defined: Group AG5 (n = 10), Group DEX (n = 10), Group NC (n = 5) and Group PT (n = 5) in which ewes were injected twice with 10 mg/kg of aglepristone and 5 ml dexamethasone in first two groups, respectively; whereas negative control and pregnancy toxemia groups received no treatment for parturition induction. Different clinical parameters associated with parturition in ewes and their newborns were investigated. Blood hematology and biochemical measurements were carried out both in ewes and lambs. Blood pH values of lambs were recorded during the study. The injection time-lambing time, injection time-vaginal discharge intervals, placental expulsion periods, placental weight and vaginal delivery interval between lambs, hematological and biochemical results were not statistically different among the groups (p 0,05). Increased NEFA and β-HBA concentrations accompanied the disease and all ewes in AG, DEX and PT Groups developed clinical pregnancy toxemia (NEFA; P = 0,009) and β-HBA; (P = 0,039). The differences in rectal body temperature of lambs were not significant (p 0,05), whereas birth weight was found statistically significant among groups (p 0,05). Blood pH, biochemical and hematologic measurements of lambs had also significant differences depending on different time points. Parturition pathology by means of incomplete cervical dilatation was severely observed in DEX Group. The results of this study show that aglepristone application in pregnancy toxemia to induce parturition could precisely control lambing time without any side effects in either mothers or lambs. Apart from these, it could be speculated that dexamethasone seems to induce parturition causing crucial pathologies, which results in important and risky changes in newborns' life. Incomplete cervical dilatation and continued ineffective uterine contractions could be a major factor of newborn losses because of placental separation and cessation of blood supply.

Matrix metalloproteinases (MMPs) and counteracting tissue inhibitors of metalloproteinases (TIMPs) are balancing extracellular matrix (ECM) formation and degradation. The latter is believed to be an important aspect for the detachment of fetal membranes postpartum when loosening the feto-matemal connection which is a prerequisite to avoid placental retention a common disease in cows leading to considerable economic loss. Membrane-type (MT) MMPs have been suggested as potential activators controlling ECM remodelling. In particular, MT1-MMP (MMP-14) is able to degrade ECM substrates and activate MMP-2 through binding TIMP-2 at the cell surface. Since the connection between the trophoblast and the maternal caruncular epithelium is supported by integrin receptors bound to ECM, we hypothesize that impaired modulation of the ECM by TIMPs/MMPs participates in the aetiology of bovine retained fetal membranes. To analyse this involvement, placentomes were collected from cows after term parturition and timely release of fetal membranes (n = 4) and cows with retained fetal membranes after various treatments for the induction of parturition using progesterone antagonist (aglepristone), PGF(2 alpha) analogue, glucocorticoid, and after elective caesarean sections (each group n = 3). The expression of MMP-14, MMP-2 and of TEMP-2 was examined by real-time-PCR, irnmunohistochemistry, Western blot and zymography. The relative mRNA expression levels of MMP-14 remained unchanged, while the expression levels of TIMP-2 and MMP-2 partly increased in animals with induced parturition and retention of fetal membranes compared to animals without placental retention. MMP-14 protein was expressed in cells of the uninucleated trophoblast, the fetal mesenchyme and maternal stoma. TIMP-2 was present exclusively in trophoblast giant cells, while MMP-2 could be detected in uninucleated trophoblast cells and the fetal mesenchyme. The presence of the activated enzyme was confirmed by zymography. In conclusion, MMP-14, MMP-2 and TIMP-2 are co-localized in the fetal compartment and therefore could influence the timely release of fetal membranes in cattle. (c) 2011 Elsevier Inc. All rights reserved.

Bu çalışma, 9-11 Temmuz 2008 tarihlerinde Viyana Üniversitesi[Avusturya]'da düzenlenen 6. International Symposium on Canine and Feline Reproduction'da bildiri olarak sunulmuştru. The present study examined the degree to which downregulation with a GnRH agonist impaired spermatogenesis and the time course of morphological and hormonal changes that occurred during recrudescence of spermatogenesis. Using a control group (group 1, n = 5) of dogs, the effect of a removable slow release GnRH-agonist implant was investigated in beagle dogs (group 2, n = 30). The implant was removed after 5 months (week 0) and three to four dogs were castrated at weeks 0, 3, 6, 9, 12, 15, 18, 21 and 24. The degree of downregulation and recrudescence of spermatogenesis was assessed by evaluation of 200 tubular cross-sections, resulting in an assigning of dogs of group 2 to testis developmental groups (DG) according to the most developed germ cell observed: DG A, spermatocytes; DG B, round spermatids; DG C, elongating spermatids and DG D, elongated spermatids. Downregulation led to an arrest of spermatogenesis at the level of spermatogonia/primary spermatocytes. The time course of recrudescence showed high individual variations and the number of dogs falling into DG A, B, C and D was 4, 3, 6 and 17 respectively. Spermatogenesis in group 2, DG D was not different from group 1 (control). In DG A, mean area of Leydig-cell nuclei was lower (p < 0.001) than in the other DG and group 1 and resembled that of juvenile dogs (group 3, n = 3); nuclei of Sertoli cells had changed from more flat/polygonal (group 1, group 2, DG C and D) to round/ovoid and had moved to a more luminal position. As indicated by basal testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations at implant removal, full downregulation had been obtained. Testosterone, LH and FSH concentrations [(g) (DF), ng/ml] increased (p < 0.05) from implant removal to DG B [T: 0.1 (1.24) vs 2.12 (2.31); LH: 0.2 (2.15) vs 1.11 (1.7); FSH: 0.37 (3.50) vs 6.37 (1.68)] and were more or less constant thereafter indicating that onset of spermatogenesis was related to an increase of plasma T occurring in a very narrow time window. Following GnRH implantation, the size of the testes and the prostate decreased by approximately 55% (p < 0.001), they increased to sizes similar to pre-treatment values following implant removal.

There is no safe and accurate method for early termination of pregnancy in the rabbit. So this study was carried out to determine the effect of aglepristone administration in preventing early pregnancy before implantation in this species. Twenty-two animals (10-12 months old, New Zealand White rabbits) were naturally mated and pregnancies were confirmed in all animals by ultrasonographic examinations on day 6 after mating (5-7.5 MHz linear array transducer Dynamic Imaging Sonostar, UK) and the animals were grouped randomly: Group I & Group III: Aglepristone (Alizin, Virbac; 10 mg/kg, subcutaneously) was injected twice, 24 h apart, on days 6 and 7 after mating (n = 5; n = 8). Group II & Group IV: The same volume of 0.9% NaCl solution was subcutaneously injected in the same interval and served as controls (n = 5; n = 3). Ultrasonographical examination of the uterus was performed daily from day 7 to day 11 post-mating to test aglepristone efficiency. Blood samples were collected between days 6 and 30, centrifuged at 3070 g for 10 min and stored at -20 degrees C. The does in aglepristone groups (Group I, III) were not pregnant whereas all animals in control groups were pregnant (Group II, IV). The does in group I & III were examined only clinically and ultrasonographically; however, does in groups III and IV were laparomized on days 6, 7, 9 and 11 post-mating to control countable implantation sites. No implantation sites were present in group III whereas they were seen obviously in group IV. Side effects were not observed. The mean serum progesterone (P4) concentrations were not significantly different between control and treated does (p > 0.05). The results indicate that aglepristone treatment on days 6 and 7 after mating could prevent pregnancy after unwanted matings without any side effects in the rabbit. Aglepristone treatments are possibly not affecting further fertilities before implantation.

A pronounced increase in fetal cortisol concentrations stimulating an increase in estrogen production at the expense of progesterone precursors in the placenta, luteolysis, and progesterone withdrawal is considered as a key event during the complex signal cascade leading to the initiation of parturition in cattle. However, there are many questions concerning the exact functional and/or temporal relationships between these individual processes which finally result in the expulsion of the calf and the timely release of the placenta. Thus, parturition was induced in 270-day pregnant cows using the progesterone receptor blocker aglepristone (group AG,n=3), the prostaglandin F2αanalog cloprostenol (group PG,n=4), and the glucocorticoid dexamethasone (group GC,n=4) to characterize the effect on maternal steroid and prostaglandin levels and to identify immediate subsequent changes in placental morphology and gene expression as compared with untreated controls sampled on day 272 (group D272,n=3) and cows during normal parturition (group NT,n=4). All calves of the treatment groups were born on days 271–272, whereas gestational length in NT cows was 280.5±1.3 days. However, none of the treatments significantly induced the prepartal remodeling of placentomes characterized by a decline in trophoblast giant cells and reduction of the caruncular epithelium. Data on placental CYP17 and COX2 expression confirm that these key enzymes are upregulated by GC, whereas placental aromatase expression was not affected by any treatment. Maternal progesterone and prostaglandin profiles suggest differential effects of the treatments on luteal function and placental or uterine prostaglandin production. The results provide new information on the initiation of parturition in cattle but raise many new questions.

In late pregnant cows, progesterone (P4) is mainly of luteal origin. However, the trophoblast may provide high local P4concentrations in the uterus. To test for the importance of a complete P4withdrawal for parturition-related processes and placental release, the P4receptor (PGR) blocker aglepristone (Ap) was administered to three cows on days 270 and 271 of pregnancy. A complete opening of the cervix was observed 46.5±7.3 h after the start of treatment. However, expulsion of the calves was impaired obviously because of insufficient myometrial activity, and placental membranes were retained for at least 10 days. Measurement of P4concentrations indicated that PGR blockage induced luteolysis. To investigate the role of P4withdrawal for the prepartal tissue remodeling of the placentomes, the caruncular epithelium was evaluated by morphometry, and the percentage of trophoblast giant cells (TGCs) relative to the total number of trophoblast cells were assessed. Caruncular epithelium in Ap-treated cows (D272+Ap) was immature (30.5±3.3%) and not different from untreated controls (elected cesarean section (CS) on day 272; D272-CS; 31.5±1.4%), whereas it was significantly reduced at normal term (D280.5±1.3; 21.0±6.1%;P=0.011). Correspondingly, the percentage of TGCs were 20.1±1.4 in D272+Ap, 22.1±4.8 in D272-CS, and 9.8±3.9 at term (P=0.001). No effect was detected on placental estrogen synthesis. The results showed that in late pregnant cows, P4withdrawal only induces a limited spectrum of the processes related to normal parturition and is not a crucial factor for the prepartal tissue remodeling in placentomes and the timely release of the placenta.

The efficacy of aglepristone treatment to induce abortion in does 15 and 16 days after mating was investigated. The pregnant does were randomly allocated into two groups: For group I, aglepristone was injected twice (10mg/kg, subcutaneously) on days 15 and 16 after mating (n=10); for group II the does got no treatment but the same volume of 0.9% sodium chloride solution was subcutaneously injected at the same days of pregnancy (n=5).group I, termination of pregnancy was successful in all does. The mean interval between the first administration of aglepristone and the beginning of vaginal discharge was 32.4+/-5.6h (range 19-72h). Complete expulsion of all fetuses was observed in four does with first occurrences of vaginal discharge on the same day. The duration between the first occurrence of vaginal discharge to expulsion of all fetuses ranged between 21 and 130h (mean 70.2+/-12.2h). As important side effects, decrease in food consumption during abortion time and irregular mating behaviour (52.3+/-2.0 days/range 46-63) were recorded. But after this time all does were mated again, 8/10 became pregnant and they whelped normal and live kittens. Group II, all does gave birth to live kittens after a mean pregnancy length of 31.2+/-0.37 days (range 30-32 days). The mean serum progesterone (P(4)) concentrations were significantly different between control and treated does after day 20 of pregnancy (P0.05). The results indicate that aglepristone treatment is effective to induce abortion in does and causes no serious negative effects on further fertility except a short non-receptive period after abortion and short time decrease in food consumption.