The moon cycle influences reproductive and productive traits in guinea pigs (Cavia porcellus) from a tropical Andean area.

There is currently innumerable evidence showing that the lunar cycle affects various reproductive aspects in farm animals. However, there is very little information on the effect of the lunar cycle on productive traits in these species. A retrospective study was conducted (2015-2018) to evaluate the influence of the lunar cycle on some reproductive and productive traits in a guinea pig (Cavia porcellus) production system in the southern Andean region of Ecuador. A total of 7352 productive and reproductive records of guinea pig females housed in 3 m2 cages with a breeding male were analyzed. The following variables were considered: offspring sex ratio, litter size per cage, number of weaned guinea pigs, mortality, individual and litter weaning weight of guinea pigs, and calving frequency. The lunar cycle was split into eight periods of ~3.7-d length each. Data were analyzed by logistic regression and general linear model, and means were compared by the least mean squares method of the SAS. The offspring sex ratio was not correlated to the lunar cycle. The lunar cycle at mating and calving influenced the litter size per cage, number of weaned, and mortality of guinea pigs. The individual and litter-weaning weights were influenced by the lunar cycle at calving. The frequency of calving was greater around the new and full moon than in the remaining periods of the lunar cycle. In conclusion, the lunar cycle influenced several productive and reproductive traits in guinea pigs, such as litter size, mortality, number of pups weaned, and individual and litter weaning weights. This valuable information may have practical applications in management of guinea pig production systems.

Angiotensin II and dengue.

Dengue is a disease caused by a flavivirus that is transmitted principally by the bite of an Aedes aegypti mosquito and represents a major public-health problem. Many studies have been carried out to identify soluble factors that are involved in the pathogenesis of this infection. Cytokines, soluble factors, and oxidative stress have been reported to be involved in the development of severe disease. Angiotensin II (Ang II) is a hormone with the ability to induce the production of cytokines and soluble factors related to the inflammatory processes and coagulation disorders observed in dengue. However, a direct involvement of Ang II in this disease has not been demonstrated. This review primarily summarizes the pathophysiology of dengue, the role of Ang II in various diseases, and reports that are highly suggestive of the involvement of this hormone in dengue.

Relationship between the concentration of anti-Müllerian hormone and antral follicle count in pasture-managed Holstein cows in the high tropics.

We evaluated the relationship between plasma levels of anti-Müllerian hormone (AMH) and the number of antral follicles at the restart of the follicular wave in crossbred Holstein cows reared under extensive grazing systems over 2500 m above sea level. The study included 140 cows from 15 farms that were in average at the 75.3 ± 2.10 d post partum. Animals were synchronized according to the following regime: day 0 = intravaginal progesterone releasing device (IPD) + estradiol benzoate (EB); day 7: withdrawal of IPD + prostaglandin; and day 8: EB, for restart of the follicular wave on day 11. On this day 11, antral follicle counts (AFCs) were made by transrectal ultrasound, and a plasma sample was taken for the determination of AMH. The mean AMH plasma level was 0.06 ± 0.03 ng/ml and the mean AFC was 17.26 ± 0.38 follicles. A strong positive linear correlation was found between these two variables (r = 0.783, r = 0.613, P < 0.0001). Cows were categorized according to AMH concentration as high (>0.09 ng/ml), intermediate (0.09-0.05 ng/ml) or low (<0.05 ng/ml). Cows with high AMH presented a higher AFC (25.0 ± 2.21 follicles) than those with low AMH (14.08 ± 2.68 follicles; P < 0.001. Our results suggest that the cut-off value of AMH = 0.09 ng/ml may be useful for selecting donors in multiple ovulation embryo transfer programs involving cows with these characteristics. Our data further suggest that AMH plasma concentration correlates with AFC and can be used as an endocrine biomarker of the number of antral follicles present at a given moment of the estrous cycle in crossbred Holstein cows raised at altitudes above 2500 m.

Lunar Cycle Influences Production of Tilapia (Oreochromis spp) Eggs in an Intensive Outdoor Production System in the Tropics.

A robust body of evidence has demonstrated that the lunar cycle plays an important role in the reproduction of fish living in natural environments. However, little is known about the influence of the moon on tilapia reproductive activity in intensive fish farming systems. This study aims to evaluate the influence of the lunar cycle on the reproductive performance of tilapias in an intensive outdoor tropical production system in Latin America. Records of two tilapia strains (Nile tilapia [Oreochromis niloticus; n = 75] and Red tilapia [Oreochromis spp.; n = 1335]) reared in concrete tanks in a commercial fish farm were analyzed. Over a 3-year period, 60,136 captures were made in intervals of 12 to 14 days and 6,600 females were manually spawned. The number of females spawned and the volume of eggs collected from each tank (n = 9) were recorded. Data was analyzed by the general linear model and means were compared by least squares means method. A very slight or no variation was observed when the lunar cycle was split into two halves (crescent and waning). The proportions of females spawned and the volume of eggs per spawned female and per female in the tank varied considerably across the eight periods of the lunar cycle, with greater values in the waning than in the crescent phase. A significantly greater proportion of tilapia spawned and yielded more eggs around the full moon than around the new moon and remaining days of the lunar cycle. The moon cycle affected the reproductive activity of tilapia, which were more reproductively active around the full moon and most of the waning phase.

Lunar Cycle Influences Reproductive Performance of Crossbred Brahman Cows Under Tropical Conditions.

Evidence has accumulated over the years indicating that the moon influences some aspects of the reproductive activity in animals and humans. However, little is known about the influence of the lunar cycle on the reproductive performance of cows under tropical conditions, where the environment strongly affects reproduction. This retrospective study was conducted with the aim of assessing the influence of the lunar cycle on some reproductive traits of tropical crossbred cows managed in a pasture-based system. Data from 5869 reproductive records from two commercial farms localized in the Maracaibo Lake Basin of Zulia State, Venezuela, were analyzed. Variables studied were first service conception rate, calving frequency, first postpartum estrous frequency, and pregnancy frequency. In addition to the lunar cycle, the effects of farm, season, and predominant breed were also considered. Data were analyzed using logistic regression and general linear model from SAS. First service conception was affected by lunar phases and predominant breed, but not by farm or season. For frequencies of calving, first postpartum estrus, and pregnancy, there was no main effect of farm, season, and predominant breed, whereas the effect of lunar phases was highly significant. First service conception was significantly greater in waning than in crescent phase of the lunar cycle. Frequencies of calving, first estrus, and pregnancy were highly correlated and showed greater figures around full moon and new moon. In conclusion, lunar cycle influenced first service conception, attaining greater values in the waning phase of the moon cycle. Frequencies of calving, first postpartum estrus, and pregnancy in crossbred cows showed a clear bimodal rhythm, whose greatest values coincided with new moon and full moon.

Tetracycline and viruses: a possible treatment for COVID-19?

Tetracyclines have been used to treat many bacterial infections. The use of these antibiotics for the treatment of viral diseases dates to the 1960s to 1970s. Over the decades, the effect of tetracyclines on the pathogenesis of viral infections has been demonstrated both clinically and experimentally. Tetracyclines can act on viral infections either through their antibacterial properties or through direct antiviral action. This review focuses on clinical and experimental data that support the use of tetracycline in treating viral infections and highlights an important approach to slowing disease progression during viral infections. Tetracycline treatment might represent a strategy for eliminating the infection or inhibiting the progression of COVID-19.

Intraovarian influence of bovine corpus luteum on oocyte morphometry and developmental competence, embryo production and cryotolerance.

Three experiments were conducted to determine influence of the bovine corpus luteum (CL) on morphometric and functional characteristics of oocytes, and subsequent embryonic development. Cumulus-oocyte complexes were aspirated from two types of cows: 1) with a CL in one ovary (CL+) and without a CL in the contralateral ovary (CL-), 2) and from cows without CL in either ovary (C). Intracellular activity of the enzyme glucose-6-phosphate dehydrogenase (G6PDH), oocyte diameter and thickness of the zona pellucida were determined (Experiment 1). Then, the rate of in vitro oocyte maturation for each ovarian category was evaluated and oocyte diameter and zona pellucida thickness were measured after maturation (Experiment 2). In Experiment 3, in vitro embryo production and cryotolerance were assessed. The oocyte diameter was greater (P < 0.01) and the zona pellucida was thinner in CL+ than in CL- (P > 0.05) or C (P = 0.0131) ovaries. Activity of G6PDH was lower in oocytes from CL+ than CL- (P < 0.01) and C (P = 0.0148) ovaries. Rate of oocyte maturation, oocyte diameter and thickness of the zona pellucida after maturation did not differ among groups. Rate of cleavage was greater in zygotes from CL+ than from CL- or C (P < 0.01); and CL+ ovaries produced more total embryos on day 7 (P < 0.05) and more blastocysts (P < 0.01) than CL- and C ovaries. Rate of expansion and hatching of day-7 vitrified-warmed blastocysts at 24 and 48 h of culture did not differ among groups. In conclusion, oocytes collected from CL+ ovaries were larger and metabolically more prepared to continue maturation than those from ovaries lacking a CL. Also, rates of cleavage and yield of blastocysts were greater for oocytes from CL+ ovaries than from CL- and C ovaries. These findings indicate that a CL influenced oocyte developmental competence and embryonic development, presumably through intraovarian interactions.

Evaluación de la capacidad de desarrollo in vitro de ovocitos bovinos provenientes de vacas con predominancia fenotípica Bos taurus y Bos indicus / Evaluation of in vitro development capacity of bovine oocytes obtained from predominantly Bos taurus and Bos indicus cows

El objetivo de este estudio fue evaluar la capacidad de desarrollo in vitro de ovocitos bovinos de vacas mestizas B. taurus y B. indicus. Los ovocitos fueron recuperados de ovarios de hembras bovinas provenientes de un matadero comercial. Para la obtención de los complejos cumulus-ovocitos (CCO) se realizó la técnica de slicing, seleccionando los ovocitos que tenían al menos una capa de células del cumulus y un citoplasma homogéneo. Los ovocitos seleccionados fueron madurados y fecundados in vitro (MIV-FIV). Se utilizó semen de un toro Brahman puro (B. indicus). Para la evaluación de la MIV y FIV todos los ovocitos se fijaron por al menos 24 h a 4°C en solución metanol-ácido acético (3:1) y teñidos con aceto-orceína al 1,1%. La tasa de maduración de ovocitos de vacas con predominancia fenotípica B. indicus fue del 66,17% mientras que las vacas con predominancia fenotípica B. taurus alcanzaron un 50,94% (P>0,05). En cuanto a la tasa de fecundación se obtuvo un 14,28 y 35,72% de ovocitos penetrados normalmente y anormales, respectivamente, para el grupo de ovocitos con predominancia fenotípica B. indicus. Mientras que para vacas con predominancia fenotípica B. taurus, un 10,22% correspondió a ovocitos penetrados normales y 19,31% de ovocitos penetrados anormales, sin encontrar diferencias estadísticamente significativas en ambos grupos. Los presentes resultados, tanto para la progresión meiótica como para las tasas de fecundación, indican que los ovocitos de vacas mestizas con predominancia fenotípica B. indicus son más competentes en las primeras etapas de desarrollo in vitro que los ovocitos de vacas mestizas con predominancia fenotípica B. taurus.

The aim of this study was to evaluate the in vitro development capacity of bovine oocytes from crossbred B. taurus and B. indicus cows. Oocytes from bovine cows were collected from commercial slaughterhouse. The cumulus-oocyte complex (COC) ovaries were obtained by Slicing technique, selecting those oocytes that had 2 to 3 layers of cumulus cells and homogeneous cytoplasm. After selection oocytes proceed with maturation (IVM) and fertilization in vitro (IVF). It used semen from a pure Brahman bull (B. indicus). For the assessment of IVM as for IVF oocytes were fixed for about 24 hours at 4°C in methanol-acetic acid (3:1) solution and stained with 1.1% aceto-orcein. The maturation rate of oocytes from cows with B. indicus phenotypic predominance was 66.17%, whereas cows with B. taurus phenotypic predominance 50.94% (P>0.05). Fertilization rate obtained in B. indicus phenotypic predominance group was 14.28% of oocytes normal penetrated and abnormal penetrated 35.72%, for cows with a phenotypic predominance B. taurus oocytes normal penetrated were 10.22% and 19.31% of abnormal oocytes penetrated. In conclusion, the present results indicate that oocytes from cows with phenotypic predominance B. indicus are more competent in the early stages of development in vitro than oocytes from cows with phenotypic predominance B. taurus.

Efecto de la suplementación con L-cisteína en la maduración in vitro de ovocitos bovinos / L-cysteine supplementation effect on the in vitro maturation of bovine oocytes

utilizada como herramienta para el estudio de diversos aspectos relacionados con la maduración de ovocitos, la fecundación y el desarrollo temprano del embrión en condiciones in vitro. La L-cisteína es un sustrato externo requerido para la síntesis del glutation en la maduración de ovocitos bovinos. Con el objetivo de evaluar el efecto de la suplementación con L-cisteína sobre la maduración in vitro de ovocitos bovinos, se llevó a cabo un experimento con ovarios obtenidos de vacas mestizas beneficiadas en una sala de matanza local. Se utilizaron tres tratamientos con diferentes concentraciones T1: 0 mM; T2: 0,1 mM y T3: 1,0 mM. Aproximadamente 400 Complejos Cumulus Ovocito (COCs) por tratamiento se maduraron en pozos de 500 µL del medio de maduración (TCM-199), distribuyéndose 50 COC por pozo en una incubadora a 5% de CO2, a 38,5°C y con humedad saturada. Los datos se analizaron por medio de un análisis de varianza (ANAVAR). No se observaron diferencias significativas entre los tratamientos en el porcentaje de ovocitos que llegaron a Metafase II (MII, T1: 72,77%, T2: 67,47% y T3: 70,43%). Los resultados indican que la suplementación con L-cisteína durante la maduración no ejerció un efecto sobre el porcentaje de ovocitos bovinos que alcanzaron el estado de MII, sin embargo se deben realizar otras investigaciones para determinar el efecto ulterior que tiene la L-cisteína adicionada en la maduración sobre la fecundación y el desarrollo embrionario in vitro.

In vitro fertilization (IVF) is now a routine technique in a number of biotechnology research laboratories worldwide. IVF is used as a tool for the study of various aspects related to oocytes maturation, fertilization and early embryo development. L-cysteine constitutes an external substrate required for synthesis of glutathione in the maturation of cattle oocytes. In order to study the effect of L-cysteine supplementation on in vitro maturation of cattle oocytes, ovaries were obtained from crossbred cows culled at a local slaughterhouse. Three different in vitro maturation treatments were utilized. Each treatment had a different concentrations of L-cysteine: T1: 0 mM, T2: 0.1 mM and T3: 1.0 mM. Approximately 400 Cumulus Oocyte Complexes (COCs) were matured in wells of 500 ìL of maturation medium (TCM-199), with 5% CO2 at 38.5°C and saturated relative humidity. Data were analyzed using analysis of variance (ANOVA). There were no significant differences between treatments in term of oocytes that arrived to Metafase II (MII, T1: 72.77%, T2: 67.47% and T3: 70.43%). Results indicate that supplementation with L-cysteine during maturation did not possitively affect the percentage of bovine oocytes that reached the M II state. Nonetheless further research should be carried out to determine the effect of L-cysteine supplementation during maturation, on fertilization and on embryonic development in vitro.

Effect of db-camp on embryonic development of bovine oocytes fertilized with sex sorted semen. / Efecto del db-cAMP Sobre el Desarrollo Embrionario de Ovocitos Bovinos Fecundados con Semen Sexado.

The objective of this study was to improve sexed bovine embryo production with sorted sperm in chemically defined conditions by supplementing the IVF medium with db-cAMP. Cumulus-oocyte complexes (COCs) were matured for 18 h in supplemented TCM-199 and fertilized with X- or Y-bearing sperm in the presence of heparin (10 µg/ml), db-cAMP (1 µM) or no treatment (control). Presumptive zygotes were cultured 54 h in g-SOF. From 72 to 144 h post- insemination (hpi) embryos were cultured in c-SOF+NEA and from 144 to 192 hpi embryos were placed in maturation medium without hormones. No significant differences were found among treatments for Y-sperm when compared to controls. A significant (P<0.01) improvement in the proportion of cleaved oocytes was found for X-sperm treated with db-cAMP (70.83%) compared to the Y-sperm inseminated oocytes treated wit db-cAMP (46.37%). Treatment with db-cAMP enabled a better (P<0.05) blastocyst formation rate (19.29%) compared to control (8.47%) and heparin (10.44%). Treatment of db-cAMP significantly increased the rate of blastocysts in X-sperm inseminated oocytes (30.77%) compared to Y-sperm inseminated oocytes treated the same (9.68%) and compared to X- and Y-sperm treated with heparin (5.88% and 15.15%, respectively) and not treated (9.68% and 7.14%, respectively, P<0.05). These results suggest that db-cAMP may prove to be an effective treatment of sorted sperm for in vitro production of female bovine embryos under chemically defined conditions.

El objetivo de este estudio fue mejorar la producción de embriones bovinos con semen sexado bajo condiciones químicamente definidas mediante la suplementación del medio de fecundación con db-cAMP. Los complejos ovocitos cumulus (COCs) fueron madurados por 18 horas en TCM-199 suplementado y fueron fecundados con espermatozoides X o Y en presencia de heparina (10 g/ml), db-cAMP (1 µM) o sin tratamiento alguno (control). Los presuntivos cigotos fueron cultivados por 54 horas en g-SOF. Desde las 72 a las 144 horas post-inseminación (hpi) los embriones se cultivaron en c-SOF+NEA y desde 144 a 192 hpi fueron colocados en medio de maduración pero sin hormonas. No se observaron diferencias entre tratamientos para los oocitos fecundados con espermatozoides Y cuando se compararon a los controles. Se observó una mejora significativa (P<0,01) en la proporción de ovocitos que se dividieron cuando fueron fecundados con espermatozoides X tratados con db-cAMP (70,83%) en comparación con los fecundados con espermatozoides Y tratados con db-cAMP (46,37%). El tratamiento con db-cAMP fue capaz de inducir una mayor (P<0,05) tasa de formación de blastocistos (19.29%) en comparación a los tratamientos control (8,47%) y heparina (10,44%). El tratamiento con db-cAMP incrementó (P<0,05) la tasa de embriones de cuatro células alcanzando el estadio de blastocisto cuando los oocitos fueron fecundados con espermatozoides X (30,77%) en comparación a cuando la fecundación se realizó con espermatozoides Y (9,68%) y en comparación a cuando se llevó a cabo con espermatozoides X o Y en presencia de heparina (5,88% y 15,15%, respectivamente) o en el tratamiento control (9,68% y 7,14%, respectivamente). Estos resultados sugieren, que el db-cAMP puede ser un tratamiento efectivo para el semen sexado, a fin de incrementar la producción in vitro de embriones bovinos hembra bajo condiciones químicamente definidas.

Calves born under tropical conditions after direct transfer of cryopreserved in vitro produced embryos

En el presente estudio se comparó el desempeño de 56 novillas doble propósito que resultaron preñadas luego de la transferencia directa de embriones producidos in vitro cultivados en un medio suplementado con suero o en uno químicamente definido. No se observaron diferencias en las tasas de aborto (30,43% vs 24,24%), distocias (52,17% vs 51,52%) y parto normal (17,39% vs 24,24%) entre las novillas que recibieron embriones cultivados en el medio suplemento con suero y las que recibieron embriones cultivados en el medio químicamente definido. El sexo de la cría afectó significativamente el porcentaje de distocias, 83,33% para machos y 50% para hembras, (P<0,05). El peso al nacimiento de los becerros tampoco se vio afectado (p>0,05) por la suplementación sérica durante el cultivo (46,86 ± 2,04 kg, para los becerros derivados de los embriones cultivados en el medio suplementado con suero y 46,28 ± 1,42 kg, para los derivados de los embriones cultivados en el medio químicamente definido) ni por el sexo de la cría (machos 47,20 ± 1,50 kg y hembras, 45,45 ± 1,84 kg). El peso de los becerros que nacieron muertos o que murieron luego del nacimiento fue significativamente (P< 0,05) mayor (51,92 ± 1,76 kg) al de los becerros que sobrevivieron (43,88 ± 1,22 kg). La sobrevivencia perinatal no se vió afectada ni la suplementación sérica durante el cultivo embrionario, ni por el sexo de los becerros o el nacimiento de un parto distócico. En conclusión, la presencia de suero en el medio de cultivo no afectó el desempeño de las novillas doble propósito que resultaron preñadas luego de la transferencia de embriones producidos in vitro. En este estudio se observó la presencia de becerros con síndrome del recién nacido gigante evidenciado por un alto peso al nacimiento y una alta tasa de abortos y distocias.

Time course of follicular development after bovine ovarian tissue transplantation in male non-obese diabetic severe combined immunodeficient mice.

OBJECTIVE: The aim of this study was to determine, with a bovine model, the appropriate interval for xenografted adult and newborn ovarian tissue to develop gonadotropin-responsive follicles. DESIGN: Controlled experiment. SETTING: Academic research laboratory. ANIMAL(S): Male non-obese diabetic (NOD) severe combined immunodeficient (SCID) mice (n = 20) were hosts of bovine ovarian tissue. Two dairy calves and one adult beef cow were donors of ovarian tissue. INTERVENTION(S): Newborn and adult bovine ovarian cortical pieces were transplanted to the SC space of intact male NOD SCID mice. Grafts were recovered after euthanasia at intervals after transplantation. MAIN OUTCOME MEASURE(S): Microscopic examination of histologic sections to determine proportions of growing follicles. RESULT(S): There was an increase in the proportion of primary and secondary follicles on day 55 after surgery for the cow and on day 124 after surgery for calf tissue compared with nongrafted and xenografted ovarian tissues recovered at previous intervals. These observed increases were accompanied by decreases in proportions of primordial follicles. Results suggest a sudden increase in the proportion of primary and secondary follicles due to progressive development of primordial follicles. CONCLUSION(S): In the NOD SCID mouse, bovine follicles survived xenotransplantation and underwent development. A longer interval was required for ovarian follicular development in calf tissues compared with that in adult cow ovarian tissues after xenotransplantation.

Efecto del factor de crecimiento epidermal (EGF) durante la maduración de oocitos sobre la reproducción in vitro de embriones bovinos / Effect of epidermal growth factor (EGF) during oocyte maturation on in vitro production of bovine embryos

El objetivo de este experimento fue investigar el efecto del Factor de Crecimiento Epidermal (EGF), durante la maduración in vitro (MIV) de oocitos bovinos, sobre el desarrollo embrionario in vitro. Los oocitos fueron obtenidos por aspiración de ovarios provenientes de vacas de matadero. Se seleccionaron 163 complejos oocitos-cumulus (COC's) con tres o más capas de células de la granulosa y fueron incubados durante 24 horas en medios de maduración ovocitaria (OMN) químicamente definidos, con los siguientes tratamientos: 1) OMM modificado (T1); 2) OMM modificado suplementado con 10 ng/ml de EGF (T2); 3) OMM modificado suplementado con suero fetal bovino al 10 por ciento (T3). Luego de la MIV, en cada medio, los oocitos fueron incubados con espermatozoides (2 x 10 elevado a la 6/ml), durante 18 horas. Los oocitos fecundados fueron denudados y cultivados in vitro hasta el estadio de blastocitos. Los oocitos madurados en T2 y T3, presentaron una tasa de división similar, pero significativamente mayor que los madurados en T1 (P<0,05). La tasa de desarrollo hasta el estadio de blastocisto fue similar en los oocitos madurados en T2 y T3. Los oocistos madurados en T3 mostraron una mayor tasa de desarrollo hasta blastocisto en comparación con T1 (P<0,01). EGF en medios químicamente definidos induce una tasa de división y desarrollo hasta blastocisto similar a la obtenida con suero fetal bovino al 10 por ciento, representando una alternativa en la maduración de oocitos para la producción in vitro de embriones bovinos

Effect of site of transplantation on follicular development of human ovarian tissue transplanted into intact or castrated immunodeficient mice.

OBJECTIVE: To study the response of human ovarian xenografts to transplantation into different sites and in different host conditions. DESIGN: Controlled experiment. SETTING: Academic research laboratory. PATIENT(S): Donated ovarian tissue from two young women. INTERVENTION(S): Human ovarian cortical pieces were transplanted either under the kidney capsule or to the subcutaneous space of intact or castrated male nonobese diabetic (NOD) severe combined immune-deficient (SCID) mice. Grafts were recovered after euthanasia. MAIN OUTCOME MEASURE(S): Microscopic examination of histologic sections to determine proportions of growing follicles, and serum estradiol concentration measurements. RESULT(S): Six months after transplantation, ovarian grafts transplanted under the kidney capsule of intact male mice had significantly higher proportions of growing follicles compared with those recovered from the castrated/kidney capsule and intact/subcutaneous groups. However, no difference was detected between the intact/kidney capsule and the castrated/subcutaneous groups. Mean estradiol concentrations in serum were nonsignificantly increased in mice with ovarian grafts compared with those in mice without a graft. CONCLUSION(S): Follicular development in xenotransplanted human ovarian tissue is influenced by the site of transplantation and the condition of the host.

Development of antral follicles in cryopreserved cat ovarian tissue transplanted to immunodeficient mice.

Ovarian cortex cryopreservation and xenotransplantation into immunodeficient mice represents a potential means for female germplasm conservation and an immediate model for investigation of folliculogenesis. The objectives of this study were to: (1) assess follicle survival after cryopreservation and transplantation of cat ovarian tissue into non-obese diabetic severely combined immunodeficient (NOD SCID) mice; and (2) evaluate the effects of gonadotropin treatments on follicular development in the transplanted tissue. Slices from the cat ovarian cortex were frozen and after thawing, transplanted under each kidney capsule of castrated male NOD SCID mice (eight xenografts in four mice). Sixty-two days after surgery, mice were randomly assigned (two per group) to gonadotropin-treated (eCG and hCG 88 h later) or control (saline-treated) groups. Twenty-four hours after the last injection, ovarian tissue was recovered and processed for histology. Fresh ovarian tissue from the same original source was similarly processed. Follicles were counted, measured, and classified as primordial, primary, secondary, or antral. Immunoreactive proliferating cell nuclear antigen (PCNA) stain was used to assess follicle viability. Microscopic examination revealed no evidence of necrosis or fibrosis. The grafts were well-vascularized, with follicles at all stages of development. Numbers of follicles in the transplanted tissue were markedly reduced compared to fresh tissue, with approximately 10% of follicles surviving freezing and transplantation procedures. Growing follicles positive for PCNA were found in all xenografts. Gonadotropin treatment did not alter the proportion of resting to growing follicles or mean follicle diameter by comparison with controls from untreated mice. By contrast, luteinization, but not ovulation, of antral follicles was observed only in grafts from treated mice. In summary, frozen-thawed cat ovarian cortex tissue not only survived xenotransplantation, it also contained follicles able to grow to antral stages. Exogenous gonadotropin treatment in this model resulted in luteinization of antral follicles but enhancement of follicular growth and ovulation did not occur.