Abstract
This study aimed to evaluate the effect of two Embryo Manipulation Solutions (EMS and EMS supplemented) in maintenance of the viability of embryos, initially using structures derived from mice (first phase). Next, the efficiency of these solutions in routines of bovine embryo transfer was evaluated (second stage). Mice embryos were used in the stages of early blastocyst, and compact morula grades I and II. These embryos were initially randomly distributed and maintained for four hours in three solutions: Modified phosphate buffered saline (PBS; Control); EMS (treatment 1), and EMS supplemented (treatment 2). Subsequently, they were cultured in TCM 199 medium and evaluated in terms of total number of cells, morphometric characteristics, ultra structural aspects, detection of cell apoptosis, and quantification of Hsp70.3 gene expression. In the second phase, these same solutions were tested in the transfer of quality I and II bovine embryos (excellent and good). These embryos were transferred fresh to 58 recipients. The results showed that the total number of cells in embryos expanded blastocyst (ExB), the number of apoptotic cells, the cell, nuclear, nucleolar diameter and the nucleus/nucleolus ratio was similar among the treatments. The pregnancy rate shown on second phase was also similar. However, the EMS supplemented expressed more Hsp70.3 than EMS. The expression of Hsp70.3 was also greater for embryos in EMS than that of EMS supplemented. The McII embryos, EMS and EMS supplemented samples also expressed more Hsp70.3 compared to control embryos. In conclusion, the tested solutions can be used in routine embryo transfer techniques, replacing modified PBS solution as an effective media in maintaining embryo viability.
Highlights
The improvement of the techniques involved in the process of in vitro production (IVP) of embryos is of fundamental importance to the study and understanding of biological mechanisms underlying embryonic development
In the preimplantation phase, genes are expressed in the blastocyst stage that are responsible for the processes that occur during cell differentiation and the implantation phase, an event that has a high percentage of embryonic mortality (Ponsuksili et al, 2002)
Bovine embryos were manipulated in these solutions and transferred to the bovine recipients, and we evaluated pregnancy rate to determine if it was feasible to substitute the media conventionally used for simpler and more stable solutions that could be stored at room temperature
Summary
The improvement of the techniques involved in the process of in vitro production (IVP) of embryos is of fundamental importance to the study and understanding of biological mechanisms underlying embryonic development. The choice of media and energy substrates has an important impact on the development and viability of embryos (Vanroose et al, 2001). According to Donnay and Leese (1999) energetic substrates, such as piruvate, glucose, lactate and amino acids play an important role in embryo development, explaining the use of different embryo manipulation and culture media. There are evidences showing that culture conditions have an impact on pre and postimplantation development and possibly the future health of the offspring (El Hajj and Haaf, 2013; Mantikou et al, 2013)
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