The use of human and bovine commercial media for oocyte maturation and embryo development in the domestic cat (Felis catus)

Effects of forskolin on cryopreservation and embryo development in the domestic cat

One of the approaches to improve cryotolerance in lipid-rich embryos is to modify their lipidome in vitro. This work is aimed to study the effects of forskolin exposure on the in vitro embryo development of the domestic cat and to evaluate how the change in lipid content affects the cryopreservation results. In vitro-derived embryos were cultured with 10 μM forskolin from the 2-cell stage for 24 h or 96/168 h to the morula/blastocyst stage. Some of the embryos treated with forskolin for 24 h were cryopreserved with slow freezing, the other ones were used to characterize their developmental rates and the amount of intracellular lipids. The in vitro exposure to forskolin had a positive effect on the embryo development, as more embryos developed to the morula stage in the forskolin-treated group (92.9%) compared to the controls (64.7%) after 120 h of in vitro culture (IVC). Nile Red staining revealed a reduced amount of intracellular lipids in the forskolin-treated embryos. The percentage of embryos developed to the morula stage was lower in the frozen-thawed embryos not treated with forskolin (54.5%), but not in the frozen-thawed forskolin-treated group (63.6%) as compared to non-frozen controls (80.8%). Thus, the exposure of embryos to forskolin in vitro reduced the level of intracellular lipids and affected embryo development before and after cryopreservation.

Mammalian Oocyte Analysis by MALDI MSI with Wet-Interface Matrix Deposition Technique

Oocytes are a special kind of biological material. Here, the individual variability of a single cell is important. It means that the opportunity to obtain information about the lipid content from the analysis of a single cell is significant. In our study, we present a method for lipid analysis based on the MALDI-based mass spectrometry imaging (MSI) approach. Our attention was paid to the sample preparation optimization with the aid of a wet-interface matrix deposition system (matrix spraying). Technical considerations of the sample preparation process, such as the number of matrix layers and the position of the spraying nozzle during the matrix deposition, are presented in the article. Additionally, we checked if changing the 2,5-dihydroxybenzoic acid (DHB) and 9-Aminoacridine (9AA) matrix concentration and their solvent composition may improve the analysis. Moreover, the comparison of paraformaldehyde-fixed versus nonfixed cell analysis was performed. We hope that our approach will be helpful for those working on lipid analyses in extraordinary material such as a single oocyte. Our study may also offer clues for anybody interested in single-cell analysis with the aid of MALDI mass spectrometry imaging and the wet-interface matrix deposition method.

The Use of Commercial Microvolume Techniques for Feline Oocyte Vitrification

This project aimed to compare the three most popular commercial oocyte vitrification techniques to determine their suitability for the vitrification of felid germlines in rescue and conservation programs. The present study aimed to determine the viability and developmental competence of feline oocytes after IVM and vitrification using a commercial vitrification method. In the first experiment, oocytes were vitrified after in vitro maturation (IVM) using the Kitazato, Cryotech, and Vitrolife methods. The oocytes were stained with fluorescein diacetate and ethidium bromide to evaluate their viability. The differences between Vitrolife and the control, Cryotech and Kitazato were statistically significant (p < 0.05), and between the control and Kitazato, were highly significant (p < 0.01). There were no significant differences between the control and Cryotech, Vitrolife and Cryotech, or Kitazato and Vitrolife. In the second part of the experiment, oocytes, after IVM and vitrification using three commercial methods, were subjected to fertilization. After vitrification, IVF was performed. We observed 35% of embryonic divisions in the group where Vitrolife and Kitazato media were used and 45% in the control group. In the presented experiment, vitrification with Vitrolife media gave slightly better results for survival and fertilization, while in the case of emergency protocol vitrification, all of the above methods may be useful to protect material derived from valuable wild felids.

High efficiency of homemade culture medium supplemented with GDF9-β in human oocytes for rescue in vitro maturation

Objective

Optimizing culture media for the incubation of immature oocytes is a vital strategy to increase the oocyte maturation rate during in vitro maturation (IVM) programs. This study evaluated the IVM and fertilization rates of human germinal vesicle (GV) and metaphase I (MI) oocytes using two different maturation media (commercial and homemade) with or without growth differentiation factor 9-β (GDF9-β). supplementation.

Methods

Immature oocytes from intracytoplasmic sperm injection (ICSI) cycles were collected and assigned to one of two IVM culture media (commercial or homemade; cleavage-stage base). After maturation, MII oocytes were examined under an inverted microscope for the presence of the polar body, zona pellucida (ZP) birefringence, and meiotic spindle (MS) visualization after maturation in four conditions (commercial or homemade medium, with or without GDF9-β. ICSI was done for matured oocytes, and fertilization was confirmed by the visualization of two distinct pronuclei and two polar bodies.

Results

No significant differences were found between the two culture media in terms of the time and rate of oocyte maturation or the rate of fertilization (p>0.05). Growth factor supplementation increased the 24-hour maturation rate for both GV and MI oocytes only in homemade medium. The maturation rate after 24 hours was higher for MI oocytes (p<0.05). Similar results were observed for MS visualization and ZP structure in both types of media (p>0.05).

Conclusion

Higher rates of oocyte maturation and fertilization were observed after application of homemade medium supplemented with GDF9-β. Therefore, this combination may be recommended as an alternative for clinical IVM programs.

A comparison of in vitro culture systems for cat embryos

The aim of this study was to compare several culture systems for cat embryos. Domestic cat oocytes were matured in vitro (IVM), fertilized (IVF), and cultured individually or in groups in drops under oil (20 μL or 50 μL) and in 16 microwell dishes (Primo Vision®). Moreover, the effects of co-culture with a) uncleaved oocytes, b) homospecific and c) heterospecific co-culture with cat and sheep companion embryos were investigated using a time-lapse system. A higher proportion of blastocysts and hatching blastocysts was observed after culture in Primo Vision® dishes compared with the classical individual (p < 0.001) and group (p < 0.05) culture systems. Culture of presumptive zygotes 16 hpi and the presence of uncleaved oocytes did not reduce blastocyst development compared with culture of embryos 24 hpi without uncleaved oocytes. Co-culture with later-stage companion cator sheep embryos accelerated development of catembryos. The highest percentage of blastocysts was obtained in the group co-cultured with sheep embryos (54%). Moreover, the blastocyst cavity formed on average 10 h faster in this group than for the control group and for embryos co-cultured with cat embryos. The proportion of hatching blastocysts was similar in the co-cultures with cat and with sheep embryos (20% vs. 22%) and significantly (p < 0.05) than in the control group (12%).

Fighting Like Cats and Dogs: Challenges in Domestic Carnivore Oocyte Development and Promises of Innovative Culture Systems

In vitro embryo production in cats and dogs still presents some challenges, and it needs to be optimized to transfer efficient protocols to related wild, endangered species. While the chemical composition of culture media has been the focus of several studies, the importance of culture substrates for oocyte and embryo culture has often been neglected. Traditional in vitro systems, i.e., two-dimensional cultures, do not resemble the physiological environments where cells develop, and they may cause morphological and functional alterations to oocytes and embryos. More modern three-dimensional and microfluidic culture system better mimic the structure and the stimuli found in in vivo conditions, and they could better support the development of oocytes and embryos in vitro, as well as the maintenance of more physiological behaviors. This review describes the different culture systems tested for domestic carnivore reproductive cells along the years, and it summarizes their effects on cultured cells with the purpose of analyzing innovative options to improve in vitro embryo production outcomes.

The frequency of collapse as a predictor of feline blastocyst quality

Domestic cats are frequently used as a research model for felid species that are threatened with extinction. Until now, the development of feline embryos has been evaluated using both classical observation methods and time-lapse monitoring (TLM). Blastocyst collapse observed using time-lapse cinematography is used as a predictor of blastocyst quality and is closely related to implantation potential. The aim of this study was to determine the relationship between the quality of domestic cat blastocysts obtained after in vitro fertilization and the frequency and duration of collapse, and of hatching. There was a significant difference in the average number of collapses and weak contractions between good and poor quality blastocysts. There was no significant difference between hatching and non-hatching blastocysts in terms of blastocyst cavity formation time or average number and duration of collapse. These results showed that the time of cavity formation was not related to blastocyst quality. The number of collapses and the occurrence of hatching were positively related to blastocyst quality, and poor quality blastocysts have, as a consequence, a reduced potential for implantation. TLM plays a significant role in cat embryo evaluation.