Effect of hCG application at different moments of the estrous cycle on corpus luteum and uterine vascularization and serum progesterone concentration in mares.
Abstract: Establishment of pregnancy after embryo transfer is the ultimate goal of an embryo transfer program and increasing pregnancy rates and reducing pregnancy loss are mandatory. The utilization of treatments to improve conception rates in recipient mares has been the focus of several research groups over the last years and the results are controversial. Some studies using human chorionic gonadotrophin (hCG) found promising results. Our hypothesis was that hCG administration would cause an additional stimulation on luteal function, uterine and luteal vascularization and progesterone concentration, and the mares would have increased uterine and cervix tone. Therefore, in the present study the effects of hCG administration to induce ovulation, on day 0 (day of ovulation) or day 5 postovulation were evaluated on corpus luteum characteristics, reproductive tract vascularization, and serum progesterone concentration from ovulation until day 15 postovulation. Groups were: G1: (control) - no hCG; G2: 2500 IU of hCG to induce ovulation when a follicle greater than 35mm and uterine edema were detected; G3: 2500 IU hCG on day 0; G4: 2500 IU hCG on day 5 postovulation. Twelve mares were randomly assigned to each group, during consecutive cycles, in a Latin Square experimental design, in a total of 48 cycles. Doppler ultrasound evaluations were performed daily from day 0 until day 15 postovulation, including mesometrial vascularity, endometrial vascularity and corpus luteum vascularity. Blood samples were collected for serum progesterone concentration. Data was analyzed using the Proc Glimmix SAS Procedure for nonparametric variables and Proc Mixed for parametric parameters. There was no treatment effect for all variables studied (P > 0.05). Characteristics were only affected by day (P < 0.05). It can be concluded that hCG administration at the time points suggested in the current study did not alter the characteristics evaluated.
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The research article is a study on the effects of human chorionic gonadotrophin (hCG) administration at varying stages of the estrous cycle to improve the chances of establishment of pregnancy after embryo transfer in mares.
Objective and Hypothesis of the Study
The primary aim of this research was to investigate if the administration of human chorionic gonadotrophin (hCG) at different stages of the estrous cycle could boost the chances of establishing pregnancy post-embryo transfer in mares.
The researchers hypothesized that hCG could stimulate luteal function, increase uterine and luteal vascularization and progesterone concentration, and boost uterine and cervical tone in mares.
Methodology
The study was conducted in a Latin Square experimental design with 48 cycles and 12 mares assigned randomly to each of four groups.
Group 1 (G1) was the control group which received no hCG. Group 2 (G2) received 2500 IU of hCG to induce ovulation when a follicle greater than 35mm and uterine edema were detected. Group 3 (G3) received 2500 IU hCG on day 0 (the day of ovulation), and group 4 (G4) received 2500 IU hCG on day 5 post-ovulation.
All mares were subjected to daily Doppler ultrasound evaluations from day 0 until day 15 post-ovulation, to study variables such as mesometrial vascularity, endometrial vascularity, and corpus luteum vascularity. Blood samples were drawn to measure the serum progesterone concentration.
Results and Conclusion
The results revealed no treatment effect for all the variables studied (P > 0.05). The characteristics were only altered by day (P < 0.05).
Contrary to the hypothesis, the administration of hCG at the suggested time points in the current study did not alter the evaluated characteristics. Thus, it had no apparent effect on the establishment of pregnancy after embryo transfer in mares.
Cite This Article
APA
Alonso MA, Silva LA, Affonso FJ, Lemes KM, Celeghini ECC, Lançoni R, Carvalho HF, de Arruda RP.
(2019).
Effect of hCG application at different moments of the estrous cycle on corpus luteum and uterine vascularization and serum progesterone concentration in mares.
Anim Reprod, 16(2), 317-327.
https://doi.org/10.21451/1984-3143-AR2018-0103
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
Silva, Luciano Andrade
Laboratory of Theriogenology Dr. O.J. Ginther, Department of Veterinary Medicine, School of Animal Sciences and Food Engineering, University of Sao Paulo, Pirassununga, São Paulo, Brazil.
Affonso, Fernanda Jordão
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
Lemes, Kleber Menegon
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
Celeghini, Eneiva Carla Carvalho
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
Lançoni, Renata
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
Carvalho, Henrique Fulanetti
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
de Arruda, Rubens Paes
Laboratory of Semen Biotechnology and Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, São Paulo, Brazil.
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