Short-term preservation of Pecari tajacu ovarian preantral follicles using phosphate buffered saline (PBS) or powdered coconut water (ACP(r)) media / Preservação de folículos ovarianos pré-antrais de Pecari tajacu por curtos períodos utilizando meios à base de solução salina fosfatada tamponada (PBS) ou água de coco em pó (ACP(r))

We compare protocols for the short-term preservation of collared peccarie's ovarian preantral follicles (PFs) by using phosphate buffered saline- (PBS) or powdered coconut water- (ACP(r)) based medium. For morphology analysis each pair of ovaries collected from six females was divided into nine fragments. One fragment was destined for morphology analysis (histology and transmission electron microscopy - TEM), constituting the control group and the other fragments were placed in tubes with PBS or ACP(r), packed in 5 L Styrofoam boxes, stored for 4h, 12h, 24h, and 36h, and then analyzed. For viability analysis a pair of ovaries from two additional females was divided into nine fragments; one fragment was immediately destined for viability analysis (Trypan blue test) and the other fragments were stored as previously described, until 24h and then analyzed. After 4h storage in ACP(r) medium, the follicular integrity was similar to control (87.8% vs 94.4%, respectively); however, ultrastructural analyses revealed swollen mitochondria as the first signals of PF degeneration. It was observed that ACP(r) (66.7%) was more efficient than PBS (49.4%) to preserve the morphological integrity after 36h storage (P<0.05); however, no differences were observed on follicular viability (P>0.05). In conclusion, the use of the ACP(r) is recommended for the short-term preservation of Pecari tajacu preantral follicles.(AU)

Compararam-se protocolos para a preservação por curtos períodos de folículos ovarianos pré-antrais (PFs) de catetos, utilizando meios à base de solução salina tamponada (PBS) ou água de coco em pó (ACP(r)). Para a análise morfológica, cada par de ovários coletados de seis fêmeas foi dividido em nove fragmentos. Um fragmento foi destinado para a análise da morfologia (histologia e microscopia eletrônica de transmissão - MET), constituindo o grupo controle, e os demais fragmentos foram colocados em tubos contendo PBS ou ACP(r), acondicionados em caixas térmicas de poliestireno expandido de 5L, armazenados durante quatro, 12, 24 e 36 horas, e, então, analisados. Para a análise da viabilidade, pares de ovários de duas fêmeas adicionais foram divididos em nove fragmentos; um deles foi imediatamente destinado à análise da viabilidade (teste com azul de Trypan), os outros fragmentos foram armazenados como descrito previamente até 24h e, então, foram analisados. Após quatro horas de armazenamento em meio ACP(r), a integridade folicular foi similar ao grupo controle (87,8% vs. 94,4%, respectivamente); contudo, a análise ultraestrutural revelou mitocôndrias edemaciadas como os primeiros sinais de degeneração dos PFs. Foi observado que o ACP(r) (66,7%) foi mais eficiente do que o PBS (49.4%) em preservar a integridade morfológica após 36h (p<0,05); entretanto, nenhuma diferença foi observada para a viabilidade folicular (P>0,05). Em conclusão, o uso da ACP(r) é recomendado para a preservação por curtos períodos de folículos pré-antrais de Pecari tajacu.(AU)

Criopreservação e xenotransplante de tecido ovariano / Cryopreservation and xenotransplantation of ovarian tissue

A criopreservação de tecido ovariano é uma biotécnica alternativa potencialmente útil na formação de bancos de células germinativas para a estocagem de DNA de espécies de alto valor zootécnico, raras ou em extinção. Além disso, gera grandes perspectivas na preservação da fertilidade de pacientes com câncer ou com problemas de infertilidade que possam provocar falha ovariana prematura. A criopreservação aliada ao processo de xenotransplante é um campo vasto para pesquisas, abrangendo desde métodos e protocolos mais efetivos de preservação até aspectos fundamentais da foliculogênese.(AU)

Cryopreservation of ovarian tissue is an alternative biotechnology potentially useful to implement gene DNA banks of livestock animals, rare and endangered species. Furthermore, it generates great prospects to save the fertility of patients with cancer or infertility problems that can cause premature ovarian failure. The cryopreservation combined with xenotransplantation is an ample field for research, rangingfrom more effective methods and protocols, including fundamental aspects of folliculogenesis.(AU)

Criopreservação e xenotransplante de tecido ovariano / Cryopreservation and xenotransplantation of ovarian tissue

A criopreservação de tecido ovariano é uma biotécnica alternativa potencialmente útil na formação de bancos de células germinativas para a estocagem de DNA de espécies de alto valor zootécnico, raras ou em extinção. Além disso, gera grandes perspectivas na preservação da fertilidade de pacientes com câncer ou com problemas de infertilidade que possam provocar falha ovariana prematura. A criopreservação aliada ao processo de xenotransplante é um campo vasto para pesquisas, abrangendo desde métodos e protocolos mais efetivos de preservação até aspectos fundamentais da foliculogênese.

Cryopreservation of ovarian tissue is an alternative biotechnology potentially useful to implement gene DNA banks of livestock animals, rare and endangered species. Furthermore, it generates great prospects to save the fertility of patients with cancer or infertility problems that can cause premature ovarian failure. The cryopreservation combined with xenotransplantation is an ample field for research, rangingfrom more effective methods and protocols, including fundamental aspects of folliculogenesis.

Early development of ruminant embryos, autonomous process or the result of a positive dialog with surrounding maternal tissues?

Background: After artificial insemination and multiple ovulation and embryo transfer (MOET), in vitro production of embryos (IVP) represents the third generation of techniques aimed at a better control of animal reproduction. This technique involves four major steps: oocyte collection, oocyte in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro development of the resulting embryos (IVD). These different steps are now well established in domestic ruminant species (cattle, sheep and goat) although the variability of the number and quality of the oocytes collected and the low viability of frozen ­ thawed in vitro produced embryos still limit the large-scale use of this promising technology. Beyond the potential use of IVP in breeding schemes, this technique is also required for the establishment of new biotechnologies such as cloning and transgenesis. Additionally, the knowledge of oocyte and embryo physiology acquired through IVP techniques may stimulate the further development of other techniques such as marker assisted and genomic selection of preimplantation embryos and also benefit to assisted procreation in human being. This paper will discuss the possible function of maternal environment in the regulation of early development and the consequences of these functions for IVP, in view to improve IVP embryos viability. Review: Comparisons between in vivo and in vitro produced embryos pointed out several differences in morphology, metabolism and gene expression. IVP embryos have a modified lipid metabolism, resulting in increased triglycerids accumulation, translating into different density. This altered lipid metabolism may account for differences in membrane structure and increased sensitivity to oxidative stress, resulting in lower cryoresistance of these IVP embryos. The identification of modified metabolic pathways leading to these lipidic disorders will provide clues for modification of culture conditions in view to restore normal lipid metabolism through appropriate precursors supplementation of the media. The natural embryo environment from fertilization to blastocyst stage is the oviduct. In vivo, oviduct epithelial cells provide ideal development support by regulating physico-chemical embryo microenvironment. Under in vitro conditions, the lack oviduct support may result in embryo exposure to toxic metabolites and oxidative stress. In addition, in vitro developing embryos may lack oviduct originated embryotrophic factors that regulate and stimulate early development in vivo. The use of co culture systems to mimic natural embryo environment in vitro may allow to improve embryo development, restore normal metabolic parameters, and increase embryo viability and cryoresistance. In addition, such co culture systems involving oviduct epithelial cells will help to identify critical development parameters and to point out potential embryotrophic factors. Conclusion: In vitro embryo production is a promising technique for improvement of selection schemes and diffusion of genetic gain through safe exchanges of embryos. To allow a lager use of this technology, improvements should be obtained in management of oocyte collection and in vitro treatment to improve its quality and in embryo in vitro development systems. A better knowledge of interactions between the developing embryo and maternal environment will allow to improve in vitro systems to produce high viability embryos.