Preservation of female fertility in humans and animal species

A detailed understanding of the cryobiology of gametes and complex tissues has led to the development of methods that facilitate the successful low temperature banking of isolated mature human oocytes, or immature oocytes in situ within fragments of human ovarian cortex. Although many outstanding research challenges remain to be addressed, the successful development of new treatments to preserve female fertility for a range of clinical indications has largely been underpinned by the conduct of extensive, fundamental research on oocytes and ovarian tissues from a number of laboratory and commercially important farm species. Indeed, the most recent evidence from large animals suggests that it is also possible to cryopreserve intact whole ovaries along with their supporting vasculature for later autotransplantation and restoration of natural fertility. This review will explore how the methods developed to preserve human oocytes and ovarian tissues can now be used strategically to support the development of conservation strategies aimed at safeguarding the genetic diversity of commercially important domestic animals and also of preserving the female germplasm for wild animals and endangered species.

Preservation of female fertility in humans and animal species

A detailed understanding of the cryobiology of gametes and complex tissues has led to the development of methods that facilitate the successful low temperature banking of isolated mature human oocytes, or immature oocytes in situ within fragments of human ovarian cortex. Although many outstanding research challenges remain to be addressed, the successful development of new treatments to preserve female fertility for a range of clinical indications has largely been underpinned by the conduct of extensive, fundamental research on oocytes and ovarian tissues from a number of laboratory and commercially important farm species. Indeed, the most recent evidence from large animals suggests that it is also possible to cryopreserve intact whole ovaries along with their supporting vasculature for later autotransplantation and restoration of natural fertility. This review will explore how the methods developed to preserve human oocytes and ovarian tissues can now be used strategically to support the development of conservation strategies aimed at safeguarding the genetic diversity of commercially important domestic animals and also of preserving the female germplasm for wild animals and endangered species.(AU)

Behavior of lateral buds of Hancornia speciosa after cryopreservation by encapsulation-vitrification / Comportamento de gemas laterais de Hancornia speciosa após criopreservação por encapsulamento-vitrificação

Hancornia speciosa is a fruitful species from Cerrado biome with high economic potential. However, the intense and disordered extractivism have caused a reduction of its population in its endemic area. In addition, seed recalcitrance negatively affects the conventional conservation of the species. Aiming to find alternatives that enable the long-term conservation of this species, the studys objective was to assess the behavior of lateral buds regrowth after cryopreservation procedures by encapsulation-vitrification technique. Sodium alginate capsules containing lateral buds were pre-cultured in liquid WPM supplemented with 1.0 M glycerol, and subsequently exposed to different concentrations of sucrose (0.3; 0.75 and 1.0 M) for 24 or 48 hours. The capsules were subjected to dehydration in silica gel or airflow hood for 0, 1, 2 and 3 hours before different incubation times in PVS2 (0, 15, 30, 60 and 120 minutes) at 0C. A high regeneration percentage of lateral buds was observed after cryopreservation of capsules treated with 0.75 M sucrose plus 1.0 M glycerol (24 hours), associated with dehydration in an airflow hood (1 hour) and immersion in PVS2 (15 minutes). Encapsulation-vitrification allowed the long-term conservation, and provided high plant material survival rates after cryopreservation of Hancornia speciosa sensitive explants.(AU)

Hancornia speciosa é uma frutífera do Cerrado com elevado potencial econômico. Entretanto, oextrativismo desordenado causou a redução populacional em sua área endêmica. Além disso, a recalcitrância dasemente afeta negativamente sua conservação convencional. Buscando alternativas de conservação para essaespécie, objetivou-se avaliar a regeneração das gemas laterais após a técnica de encapsulamento-vitrificação.Cápsulas de alginato de sódio contendo gemas laterais foram pré-cultivadas em meio WPM acrescido de 1,0 Mde glicerol e, posteriormente, imersas em diferentes concentrações de sacarose (0,3; 0,75 e 1,0 M) por 24 ou 48horas. As cápsulas foram submetidas à desidratação em sílica gel ou em fluxo laminar por 0, 1, 2 e 3 horas antes desua incubação em diferentes tempos de PVS2 (0, 15, 30, 60 e 120 minutos). Elevada porcentagem de regeneraçãode gemas laterais foi observada após a criopreservação de cápsulas tratadas com 0,75 M de sacarose + 1,0 M deglicerol por 24 horas, associado com a desidratação em fluxo laminar (1 hora) e imersão em PVS2 (15 minutos).O encapsulamento-vitrificação é eficiente para a conservação de longo prazo e permite a obtençao de altas taxas desobrevivência após a criopreservação de explantes sensíveis (gemas laterais) de Hancornia speciosa.(AU)

Sazonalidade e qualidade do sêmen fresco e criopreservado de touros Pantaneiro e Nelore / Seasonality and quality of fresh and cryopreserved semen of Pantaneiroand Nellore bulls

Objetivou-se avaliar o efeito da estação do ano sobre a qualidade do sêmen fresco e criopreservado de reprodutores Pantaneiros(Bos taurus) criados em condições tropicais. Foram utilizados 7 touros Pantaneiros e 3 Nelores (controle), dos quais foi aferidocircunferência escrotal, consistência testicular e após a coleta e congelamento do sêmen realizada análise de motilidade, vigor,defeitos menores, maiores e totais, concentração, integridade de membrana plasmática e acrossomal para sêmen fresco e alémdestas, estresse oxidativo para sêmen criopreservado. O experimento foi conduzido em delineamento inteiramente casualizado, earranjo fatorial 2x2 (2 raças e 2 estações do ano). A raça, estação do ano ou a interação entre eles, não alteraram significativamenteas médias de circunferência escrotal, consistência testicular, motilidade, vigor, concentração, integridade de membrana acrossomale porcentagem de defeitos menores. A integridade da membrana plasmática no sêmen fresco sofreu efeito da estação do ano efoi menor no inverno em ambas raças (95,76 ± 1,77% vs. 87,07 ± 4,78% P=0,03). A estação do inverno aumentou a porcentagemde defeitos maiores (29,15% vs. 16,44%, P<0,01) e totais (17,49% vs. 30,45%, P<0,01). Os parâmetros do sêmen congeladonão foram influenciados pela raça, estação do ano ou interação entre elas. Portanto, nas condições edafoclimáticas estudadas,os reprodutores Pantaneiros apresentaram redução na sua qualidade seminal na estação do inverno.(AU)

The aim of the present study was to evaluate the effect of seasonality on the quality of fresh and cryopreserved semen of Pantaneirobreed (Bos taurus) bulls raised under tropical conditions. Scrotal circumference and testicular consistency were performed inseven Pantaneiro and three Nellore (control) bulls. Sperm motility, vigor, minor, major and total defects, concentration, plasmaand acrosomal membrane integrity were assessed in fresh and post-thawed semen. Additionally, oxidative stress was determinedin post-thawed semen samples. The experiment was done in a complete randomized design, with a 2x2 factorial arrangement (2breeds and 2 seasons). Breed, season of the year or the interaction of both did not alter scrotal circumference, testicular consistency,motility, vigor, concentration, acrosomal membrane integrity and percentage of minor defects (P<0.05). Plasma membrane integrityof fresh semen was affected by the season and was smaller in winter in both breeds (95.76 ± 1.77% vs 87.07 ± 4.78%, P=0.03).Nevertheless, also in the winter there was an increase in the percentage of major (29.15% vs 16.44%, P<0.01) and total defects(17.49% vs. 30.45%, P<0.01) in fresh semen samples. Breed, season or interaction of both did not influence the sperm parametersof cryopreserved semen. Thus, in the studied climatic conditions, the Pantaneiro breed bulls present decrease in semen qualitymainly in the winter season.(AU)

Efeito do óleo de mauritia flexuoxa sobre a integridade estrutural de espermatozoides caprinos criopreservados / Mauritia flexuosa oil effect on the structural integrity of sperm cryopreserved goats

This study aimed to evaluate the effect of Mauritia flexuosa oil on the structural integrity of spermcryopreserved goats. four clinically healthy goats were used. thirty-two samples were taken, with dilution inTris-egg yolk-glycerol and diluent containing vegetable oil (Mauritia flexuoxa). After cryopreservation, thesamples were thawed and evaluated for sperm plasma membrane integrity parameters of acrosome andmitochondrial activity. The percentage of cells with mitochondrial activity and acrosome integrity were higher inthe control group (P <0.05). There was no difference in the percentage of cells with membrane integrity betweenthe groups (P > 0.05). The addition of the seminal Mauritia flexuoxa thinner not kept mitochondrial activityparameters and plasma membrane integrity of sperm at levels similar to conventional thinner, but was able tomaintain the integrity of the sperm plasma membrane.(AU)

Efeito do óleo de mauritia flexuoxa sobre a integridade estrutural de espermatozoides caprinos criopreservados / Mauritia flexuosa oil effect on the structural integrity of sperm cryopreserved goats

This study aimed to evaluate the effect of Mauritia flexuosa oil on the structural integrity of spermcryopreserved goats. four clinically healthy goats were used. thirty-two samples were taken, with dilution inTris-egg yolk-glycerol and diluent containing vegetable oil (Mauritia flexuoxa). After cryopreservation, thesamples were thawed and evaluated for sperm plasma membrane integrity parameters of acrosome andmitochondrial activity. The percentage of cells with mitochondrial activity and acrosome integrity were higher inthe control group (P 0.05). The addition of the seminal Mauritia flexuoxa thinner not kept mitochondrial activityparameters and plasma membrane integrity of sperm at levels similar to conventional thinner, but was able tomaintain the integrity of the sperm plasma membrane.

Germination and gametophyte development of Cyathea corcovadensis (Raddi) Domin (Cyatheaceae) from spores stored at low temperatures / Germinação e desenvolvimento gametofítico de Cyathea corcovadensis (Raddi) Domin (Cyatheaceae) com esporos armazenados em baixas temperaturas

The tree fern Cyathea corcovadensis (Raddi) Domin is an endangered species in the state of Rio Grande do Sul, Brazil. It currently occurs only in the northern segment of the coastal region. Spore storage would help in conservation programs since it maintains genetic variability and provides material for in vitro cultures. Current study evaluates the effect of low temperatures combined to different spore storage times on the germination and initial gametophyte development of C. corcovadensis. Spores were divided into two groups: spores of the first group were sowed immediately in Meyer culture medium with nystatin, at pH 4.0, while spores of the second group were stored at 7, -20 and -196C during 60, 120, 180, and 365 days and then sowed in the same medium. Spore storage at 7 and -196C for 365 days not only provided higher germination percentages than those reported for recently-collected spores but also stimulated gametophytic development. The latter was demonstrated by the higher percentages of laminar gametophytes in these treatments. The possibility of storing spores provides material for in vitro experiments, which is of special interest for C. corcovadensis due to its ornamental potential and conservation status.(AU)

A samambaia arborescente Cyathea corcovadensis (Raddi) Domin está em perigo de extinção no Estado do Rio Grande do Sul, Brasil, ocorrendo somente no norte da região costeira. O armazenamento de esporos pode auxiliar programas de conservação, uma vez que oferece a possibilidade de manutenção da variabilidade genética e fornece material para culturas in vitro. O objetivo deste estudo foi avaliar o efeito de temperaturas baixas combinadas com diferentes tempos de armazenamento de esporos sobre a germinação e o desenvolvimento inicial de gametófitos de C. corcovadensis. Os esporos foram divididos em dois grupos: os do primeiro grupo foram semeados imediatamente em meio de cultura Meyer com nistatina, com pH 4,0 e os do segundo grupo foram armazenados a 7, -20 e -196C durante 60, 120, 180 e 365 dias e então semeados no meio supra mencionado. O armazenamento de esporos a 7 e -196C durante 365 dias propiciou porcentagens de germinação superiores àquelas observadas para esporos recém coletados e também estimulou o desenvolvimento gametofítico, o que foi demonstrado pelos elevados valores de porcentagem de gametófitos laminares observados nestes tratamentos. A possibilidade de armazenar esporos oferece material para experimentos in vitro, o que é de especial interesse para C. corcovadensis, considerando seu potencial ornamental e estado de conservação.(AU)

Ovarian cryopreservation and grafting: its potential for human reproductive biology and animal conservation

Ovarian cryobanking has considerable potential for fertility preservation and restoration and has been used to establish term pregnancies in mice, rats, sheep and humans, yet there is scope for progress towards in vitro and in vivo strategies to A) screen and improve outcomes of cryopreservation procedures and to minimize ischemic damage following grafting, B) monitor folliculogenesis and hormonal feedback, C) screen for, and remove, malignant cells, D) generate antral follicles containing normal mature fertilizable oocytes even when orthotopic autografting is not possible, and E) combine ovarian cryopreservation with more advanced reproductive technologies such as nuclear transfer (for animals only). In species such as mice a very diverse range of both cryopreservation and grafting strategies (including xenografting) has successfully generated live young. Human ovarian grafting is still a rare procedure and it is therefore encouraging that several babies have now been born. Progress has been slowest for species where compatible recipients are seldom available, such as with rare and endangered species. For these, further significant breakthroughs will be needed before cryobanked material can be reliably and efficiently used to generate new offspring.

Ovarian cryopreservation and grafting: its potential for human reproductive biology and animal conservation

Ovarian cryobanking has considerable potential for fertility preservation and restoration and has been used to establish term pregnancies in mice, rats, sheep and humans, yet there is scope for progress towards in vitro and in vivo strategies to A) screen and improve outcomes of cryopreservation procedures and to minimize ischemic damage following grafting, B) monitor folliculogenesis and hormonal feedback, C) screen for, and remove, malignant cells, D) generate antral follicles containing normal mature fertilizable oocytes even when orthotopic autografting is not possible, and E) combine ovarian cryopreservation with more advanced reproductive technologies such as nuclear transfer (for animals only). In species such as mice a very diverse range of both cryopreservation and grafting strategies (including xenografting) has successfully generated live young. Human ovarian grafting is still a rare procedure and it is therefore encouraging that several babies have now been born. Progress has been slowest for species where compatible recipients are seldom available, such as with rare and endangered species. For these, further significant breakthroughs will be needed before cryobanked material can be reliably and efficiently used to generate new offspring.(AU)