Anti-Müllerian hormone as a predictor of the number of oocytes obtained during in vitro fertilization treatments.

OBJECTIVE: To evaluate the correlation between serum anti-Müllerian hormone (AMH) and the number of oocytes retrieved after controlled ovarian stimulation for in vitro fertilization treatments and determine cut-off values predictive of poor and high response to stimulation. METHODS: It was performed a retrospective observational study that included 1003 cycles of controlled ovarian stimulation carried between February 2017 and December 2023 at a Medically Assisted Procreation Centre. The exclusion criteria were the following: serum AMH levels obtained more than 6 months prior to the start of the ovarian stimulation, the presence of a single ovary, non-Caucasian ethnicity, a controlled ovarian stimulation cycle performed for the purpose of oocyte donation or fertility preservation, a documented diagnosis of endometriosis, a documented history of ovarian surgery and the absence of essential data for the study in the medical records (absence of the number of oocytes obtained or the AMH value). Poor response to stimulation was defined as ≤ 3 oocytes retrieved, and high response was defined as > 15 oocytes. The correlation between variables was calculated using Spearman's correlation test and cut-off values were determined using ROC (Receiver Operating Characteristic) curves. RESULTS: AMH exhibited a significantly positive correlation with the number of oocytes retrieved (Spearman's correlation coefficient = 0.60, p<0.01). The predictive cut-off for poor ovarian response was 0.72 ng/mL (specificity of 95.13%, sensitivity of 43.23%), and the predictive cut-off for high ovarian response was 4.77 ng/mL (specificity of 89.86%, sensitivity of 38.22%). CONCLUSIONS: Serum AMH proved to be a good predictor of the ovarian response to controlled ovarian stimulation for in vitro fertilization treatments, which makes it useful in supporting clinical decision-making. However, it should not be used as an absolute discriminator of poor or high ovarian response.

Wnt-5a/Ca2+ pathway modulates endogenous current and oocyte structure of Xenopus laevis.

Wnt signaling plays an essential role in cellular processes like development, maturation, and function maintenance. Xenopus laevis oocytes are a suitable model to study not only the development but also the function of different receptors expressed in their membranes, like those receptors expressed in the central nervous system (CNS) including Frizzled 7. Here, using frog oocytes and recordings of endogenous membrane currents in a two-electrode path configuration along with morphological observations, we evaluated the role of the non-canonical Wnt-5a ligand in oocytes. We found that acute application of Wnt-5a generated changes in endogenous calcium-dependent currents, entry oscillatory current, the membrane's outward current, and induced membrane depolarization. The incubation of oocytes with Wnt-5a caused a reduction of the membrane potential, potassium outward current, and protected the ATP current in the epithelium/theca removed (ETR) model. The oocytes exposed to Wnt-5a showed increased viability and an increase in the percentage of the germinal vesicle breakdown (GVBD), at a higher level than the control with progesterone. Altogether, our results suggest that Wnt-5a modulates different aspects of oocyte structure and generates calcium-dependent endogenous current alteration and GVDB process with a change in membrane potential at different concentrations and times of the exposition. These results help to understand the cellular effect of Wnt-5a and present the use of Xenopus oocytes to explore the mechanism that could impact the activation of Wnt signaling.

Successful equine in vitro embryo production by ICSI - effect of season, mares' age, breed, and phase of the estrous cycle on embryo production.

This retrospective study aimed at identifying factors that contribute to the success of equine in vitro embryo production by intracytoplasmic sperm injection (ICSI). A total of 7993 ovum pick-up (OPU) sessions were performed, totaling 2540 donor mares and semen from 396 stallions. Oocytes were aspirated at multiple sites in Brazil and were sent to the laboratory, within 6 h from OPU, in pre-maturation medium where they were in vitro matured (IVM) followed by ICSI and in vitro embryo culture for 7-8 days. The number of recovered oocytes, matured oocytes, cleaved embryos and blastocysts were used to explore the effect of age and breed of the donor mare, time of year in which the mare was aspirated and phase of the estrous cycle on the day of follicular aspiration. Mares between 6 and 15 years old were superior to other age groups in most parameters evaluated, including the average number of blastocysts per OPU. The impact of age was similar when evaluated within two breeds, American Quarter Horse (AQHA) and Warmblood mares. We observed that breed (AQHA, Warmblood, Crioulo, Lusitano and Mangalarga) had an important effect on most of the parameter evaluated, including number of oocytes recovered, blastocysts produced per OPU, and blastocyst rates. The overall impact of season was less pronounced than age and breed, with the only statistically significant difference being a higher rate of oocyte maturation during the summer season. Finally, most of the parameters evaluated were superior in follicular phase mares, with or without dominant follicle than luteal phase mares. In conclusion, this retrospective study revealed that breed, age, season and stage of estrous at the time of OPU are all important parameters for the success of equine embryo production by ICSI. This technology enables producing embryos all-year-round from mares of different breeds and ages from OPU-derived oocytes collected at multiple sites.

In vitro culture of mechanically isolated murine primary follicles in the presence of human platelet lysate PLTMax.

OBJECTIVE: To develop a system for the culture of murine preantral ovarian follicles using Human Serum Albumin (HSA) and Human Platelet Lysate (PLTMax). METHODS: Mechanically isolated preantral follicles (N=146) were obtained from Swiss mice and cultured in DMEM:F12 medium for ten days in a 96-well plate with conical bottom. The medium was supplemented with penicillin, streptomycin, and equine chorionic gonadotropin. Additional proteins were tested in 4 test groups: G1: human serum albumin (HSA), G2: human platelet lysate (PLTM), and G3 and G4: HSA + PLTMax at lower and higher concentrations, respectively. Cellular vitality and oocyte morphology were evaluated on day 11 of culture. RESULTS: The highest follicular growth (3.4 fold) was achieved in HSA (G1), while a significantly lower (1.8 fold) growth was achieved in the presence of PLTM (G2, G4) and even further reduced (1.2 fold) when HSA and PLTM were combined (G3). Cellular vitality was close to 70-80% among the four groups, and the highest number of intact oocytes were found in G1. CONCLUSIONS: PLTM did not improve follicular development and oocyte maturation compared to HSA but preserved cell vitality.

Variations in metabolic parameters of in vitro matured porcine oocytes after vitrification-warming.

Background: As the porcine oocyte is the most sensitive to low-temperature damage, it has been difficult to cryopreserve compared to those from other domestic animals. However, at present, vitrification is used as a method for the cryopreservation of both oocytes and embryos in this species. Aim: Our aim was to analyze alterations in metabolic parameters in vitrified-warmed in vitro matured porcine oocytes at different post-warming recuperation times. In addition, metaphase II plate recovery time analysis, in vitro fertilization, and intracytoplasmic sperm injection were carried out to evaluate oocyte recovery capacity. Methods: Oocytes were vitrified-warmed and then incubated for 0, 3, or 21 hours post-warming to assess biochemical parameters. Results: Oocyte viability and morphology were not affected by vitrification-warming. Cytosolic oxidative status, active mitochondria, and reactive oxygen species levels presented changes at the different time points in control and vitrified-warmed oocytes (p < 0.05) as well as differences between both groups (p < 0.05). Nicotinamide adenine dinucleotide phosphate levels remained constant throughout different recuperation times but were significantly lower in vitrified-warmed oocytes (p < 0.05). Metaphase II plate recovery occurred mostly between 3 and 4 hours post-warming, but the percentage of metaphase II was reduced by vitrification-warming. Sperm head decondensation and pronuclear formation capacities were not modified. Conclusion: In conclusion, vitrification-warming generates biochemical alterations in porcine oocytes that would be, in part, responsible for affecting their performance. Therefore, although the technique is a valid alternative for porcine oocyte cryopreservation, the protocols should be adapted to minimize those alterations.

The light chain of tetanus toxin bound to arginine-rich cell-penetrating peptide inhibits cortical reaction in mouse oocytes.

Introduction: Cortical reaction is a secretory process that occurs after a spermatozoon fuses with the oocyte, avoiding the fusion of additional sperm. During this exocytic event, the cortical granule membrane fuses with the oocyte plasma membrane. We have identified several molecular components involved in this process and confirmed that SNARE proteins regulate membrane fusion during cortical reaction in mouse oocytes. In those studies, we microinjected different nonpermeable reagents to demonstrate the participation of a specific protein in the cortical reaction. However, the microinjection technique has several limitations. In this work, we aimed to assess the potential of cell-penetrating peptides (CPP) as biotechnological tools for delivering molecules into oocytes, and to evaluate the functionality of the permeable tetanus toxin (bound to CPP sequence) during cortical reaction. Methods: Arginine-rich cell-penetrating peptides have demonstrated the optimal internalization of small molecules in mammalian cells. Two arginine-rich CPP were used in the present study. One, labeled with 5-carboxyfluorescein, to characterize the factors that can modulate its internalization, and the other, the permeable light chain of tetanus toxin, that cleaves the SNAREs VAMP1 and VAMP3 expressed in mouse oocytes. Results: Results showed that fluorescent CPP was internalized into the oocyte cytoplasm and that internalization was dependent on the concentration, time, temperature, and maturation stage of the oocyte. Using our functional assay to study cortical reaction, the light chain of tetanus toxin bound to arginine-rich cell-penetrating peptide inhibited cortical granules exocytosis. Discussion: Results obtained from the use of permeable peptides demonstrate that this CPP is a promising biotechnological tool to study functional macromolecules in mouse oocytes.

O hormônio antimulleriano e a reserva ovariana: uma revisão integrativa da literatura / The anti-mullerian hormone and the ovarian reserve: an integrative literature review

O hormônio antimulleriano é secretado pelas células da granulosa dos folículos que estão em desenvolvimento no ovário. Por meio da sua dosagem, é possível avaliar a reserva ovariana. A mulher tem seu número máximo de oócitos no perío- do fetal, mas, conforme o tempo passa, existe uma queda do número de células germinativas. Desse modo, para mulheres que têm o desejo de engravidar, a dosa- gem de hormônios e a avaliação da reserva ovariana podem ajudar no processo. O objetivo do estudo foi encontrar evidências na literatura que comprovem que o hormônio antimulleriano é o melhor marcador da reserva ovariana. Para isso, foi realizada uma revisão integrativa, classificada como qualitativa; a busca de da- dos foi realizada no PubMed, utilizando a seguinte palavra-chave: "hormônio anti- mulleriano (HAM)". Foram encontrados oito artigos que abordavam diretamente o tema, e há evidências que corroboram a hipótese de que o hormônio antimulleria- no é um bom marcador da reserva ovariana, sendo necessários mais estudos para determinar a sua superioridade.

The anti-mullerian hormone is secreted by the granulosa cells of follicles that are developing in the ovary. Though its dosage is possible to evaluate the ovarian re- serve. Women have their maximum number of oocytes in the fetal period, but there is a decrease in the number of germinative cells as time goes by. Thus, women that desire to get pregnant can have hormones dosed and the ovarian reserve evalua- ted to help them with this process. The objective of this study was to find evidence in the literature that proves that the anti-mullerian hormone is the best marker of ovarian reserve. For this purpose, an integrative review was conducted, using the key word: "anti-mullerian hormone (AMH)". Eight articles were found on the subject and there is evidence that proves the hypothesis of the anti-mullerian hormone as a good marker, however more studies are needed to determine its superiority.

Insulin-like growth factor-1 improves in vitro meiotic resumption of dromedary camel (Camelus Dromedarius) oocytes.

Despite relatively high maturation rate of in vitro matured oocytes in the dromedary camel, however, blastocyst production is very low after in vitro fertilization (IVF). Herein, the influences of oocyte collection method (follicular aspiration vs slicing; Experiment I), the addition of Insulin-like growth factor I (IGF-I) to the maturation medium (Experiment II) on in vitro maturation (IVM) of oocyte were investigated. Although the nuclear maturation did not differ regardless of collecting method, follicular aspiration led to lower degeneration rates than those in controls (P < 0.05). The percentages of oocytes at MII were greater in the presence of IGF-1 than in its absence (71.9% vs 48.4%, respectively, P<0.05). Additionally, the percentages of degenerated oocytes were higher in the control group compared to oocytes cultured in the presence of IGF-I (23.6% vs 10.4%, respectively, P<0.05). IGF-I treatment improved the quality of MII matured oocytes as evidenced by the decrease of cathepsin B (CTSB) activity, a marker of poor quality oocytes, when compared to control ones (P < 0.05). In conclusion, follicular aspiration decreased the degeneration rate; however, it had no effect on completion of maturation. IGF-I enhanced the IVM of oocyte and decreased degeneration rate.

An exploratory study of motivations for elective oocyte cryopreservation. / Estudio exploratorio de las motivaciones para la criopreservación de ovocitos en forma electiva.

Introduction: Oocyte vitrification is a scientific advance that has changed the reproductive perspective of human society. This procedure has been offered as an alternative to the voluntary postponement of pregnancy, giving women a new perspective on their reproductive autonomy. The number of women who consult and then choose to freeze oocytes has increased almost exponentially in Chile and throughout the world. There is little knowledge about the motivation, experience, and results of elective oocyte cryopreservation in Chile. The objective was to know the motivation, experience, and future reproductive desire of the women who underwent this technique. Methods: Cross-sectional descriptive study based on a questionnaire sent by e-mail in which females who had previously undergone elective oocyte cryopreservation between January 2011 and December 2019 at Clínica Alemana, Santiago, Chile, participated. Results: Of 342 women who had completed a cycle of elective oocyte cryopreservation, 193 agreed to participate, and of these, 98 (51%) answered the survey satisfactorily. Women who underwent this procedure for medical indication, including endometriosis, cancer, and low ovarian reserve, were excluded. The most frequent reason for the procedure was age (44%). Concerning the procedure: 94% do not regret having it done, and 74% of the women believe that they will use their oocytes at some point in their lives. Finally, from the time of oocyte cryopreservation to date, 11% of the surveyed women have used their vitrified oocytes, and 27% have become pregnant. Conclusions: Women who undergo elective oocyte cryopreservation for social reasons are mainly women without a partner whose main motivation is their reproductive age. The vast majority do not regret doing so.

Introducción: La vitrificación de óvulos es un avance científico que ha cambiado la perspectiva reproductiva de la sociedad humana. Este procedimiento se ha ofrecido como alternativa a la postergación voluntaria del embarazo, confiriéndole a la mujer una nueva perspectiva en su autonomía reproductiva. El número de mujeres que consultan y luego optan por congelar ovocitos ha aumentado en forma casi exponencial en Chile y en todo el mundo. En nuestro país, hay poco conocimiento acerca de la motivación, experiencia y resultados de la criopreservación electiva de ovocitos en Chile. El objetivo fue conocer la motivación, experiencia y el deseo reproductivo futuro de este grupo de mujeres sometidas a esta técnica. Métodos: Estudio descriptivo transversal, basado en un cuestionario enviado por correo electrónico en el que participaron mujeres que se habían sometido previamente a criopreservación electiva de ovocitos entre enero de 2011 y diciembre de 2019 en Clínica Alemana, Santiago de Chile. Resultados: De 342 mujeres que habían completado un ciclo de criopreservación electiva de ovocitos, 193 aceptaron participar y de estas, 98 (51%) de las mujeres contestaron la encuesta en forma satisfactoria. Se establecieron criterios de exclusión a aquellas mujeres que se habían sometido a este procedimiento por indicación médica como la endometriosis, el cáncer y la baja reserva ovárica. El motivo más frecuente para realizarse el procedimiento fue la edad (44%). En relación al procedimiento; el 94% no se arrepiente de haberlo realizado y 74% de las mujeres cree que utilizará sus ovocitos en algún momento de su vida. Por último, desde que se realizaron la criopreservación de ovocitos a la fecha, el 11% de las mujeres encuestadas ha usado sus ovocitos vitrificados y 27% ha logrado embarazarse con estos. Conclusión: Las mujeres que se someten a criopreservación electiva de ovocitos por razones sociales, son principalmente mujeres sin pareja que tiene como motivación principal su edad reproductiva y la gran mayoría de ellas no se arrepienten de haberlo realizado.

Estudio exploratorio de las motivaciones para la criopreservación de ovocitos en forma electiva / An exploratory study of motivations for elective oocyte cryopreservation

INTRODUCCIÓN: La vitrificación de óvulos es un avance científico que ha cambiado la perspectiva reproductiva de la sociedad humana. Este procedimiento se ha ofrecido como alternativa a la postergación voluntaria del embarazo, confiriéndole a la mujer una nueva perspectiva en su autonomía reproductiva. El número de mujeres que consultan y luego optan por congelar ovocitos ha aumentado en forma casi exponencial en Chile y en todo el mundo. En nuestro país, hay poco conocimiento acerca de la motivación, experiencia y resultados de la criopreservación electiva de ovocitos en Chile. El objetivo fue conocer la motivación, experiencia y el deseo reproductivo futuro de este grupo de mujeres sometidas a esta técnica. MÉTODOS: Estudio descriptivo transversal, basado en un cuestionario enviado por correo electrónico en el que participaron mujeres que se habían sometido previamente a criopreservación electiva de ovocitos entre enero de 2011 y diciembre de 2019 en Clínica Alemana, Santiago de Chile. RESULTADOS: De 342 mujeres que habían completado un ciclo de criopreservación electiva de ovocitos, 193 aceptaron participar y de estas, 98 (51%) de las mujeres contestaron la encuesta en forma satisfactoria. Se establecieron criterios de exclusión a aquellas mujeres que se habían sometido a este procedimiento por indicación médica como la endometriosis, el cáncer y la baja reserva ovárica. El motivo más frecuente para realizarse el procedimiento fue la edad (44%). En relación al procedimiento; el 94% no se arrepiente de haberlo realizado y 74% de las mujeres cree que utilizará sus ovocitos en algún momento de su vida. Por último, desde que se realizaron la criopreservación de ovocitos a la fecha, el 11% de las mujeres encuestadas ha usado sus ovocitos vitrificados y 27% ha logrado embarazarse con estos. CONCLUSIÓN: Las mujeres que se someten a criopreservación electiva de ovocitos por razones sociales, son principalmente mujeres sin pareja que tiene como motivación principal su edad reproductiva y la gran mayoría de ellas no se arrepienten de haberlo realizado.

INTRODUCTON: Oocyte vitrification is a scientific advance that has changed the reproductive perspective of human society. This procedure has been offered as an alternative to the voluntary postponement of pregnancy, giving women a new perspective on their reproductive autonomy. The number of women who consult and then choose to freeze oocytes has increased almost exponentially in Chile and throughout the world. There is little knowledge about the motivation, experience, and results of elective oocyte cryopreservation in Chile. The objective was to know the motivation, experience, and future reproductive desire of the women who underwent this technique. METHODS: Cross-sectional descriptive study based on a questionnaire sent by e-mail in which females who had previously undergone elective oocyte cryopreservation between January 2011 and December 2019 at Clínica Alemana, Santiago, Chile, participated. RESULTS: Of 342 women who had completed a cycle of elective oocyte cryopreservation, 193 agreed to participate, and of these, 98 (51%) answered the survey satisfactorily. Women who underwent this procedure for medical indication, including endometriosis, cancer, and low ovarian reserve, were excluded. The most frequent reason for the procedure was age (44%). Concerning the procedure: 94% do not regret having it done, and 74% of the women believe that they will use their oocytes at some point in their lives. Finally, from the time of oocyte cryopreservation to date, 11% of the surveyed women have used their vitrified oocytes, and 27% have become pregnant. CONCLUSIONS: Women who undergo elective oocyte cryopreservation for social reasons are mainly women without a partner whose main motivation is their reproductive age. The vast majority do not regret doing so.

Fertility preservation: a case report of a newborn following 13 years of oocyte cryopreservation.

OBJECTIVE: Oocyte cryopreservation enables the storage of genetic material, especially in situations where the ovarian function is compromised, also for women desiring to postpone maternity. Before 2012, oocyte cryopreservation was still experimental, and the success of the procedure was uncertain; however, it was the only possibility that women had for fertility preservation. Thus, we aim to report a case of a birth after 13 years of elective oocyte cryopreservation. CASE DESCRIPTION: At 49 years of age, the patient returned to our reproductive center with the desire to get pregnant, using oocytes that had been frozen for 13 years. The endometrium was prepared, and the oocytes were thawed using the slow procedure method. Four of the six oocytes thawed survived (66%) and were inseminated; three fertilized and started their development. The transfer of two embryos on the third day of development was performed. Clinical pregnancy was confirmed via ultrasound and came to term with the birth of a healthy boy. DISCUSSION: Although the vitrification procedure has shown to be a better cryopreservation technique when compared to slow freezing, the latter represented an important role when patients wanted to cryopreserve oocytes in the early 2000s. Even many years later, this technique reveals its efficacy, preserving the viability and quality of oocytes stored in nitrogen tanks. After a literature review, this case seems to be the largest interval between oocyte cryopreservation and its use, with achieved pregnancy, in Brazil.

Oocyte quality in adapted Bos taurus taurus cows.

The objective of the current study was to determine the performance of creole cows of the Chino Santandereano breed in the ultrasound-guided follicular aspiration technique (OPU) and the quality of oocytes recovered. A total of 15 multiparous cows were selected from a herd located in the department of Santander with tropical climate. The cows were submitted to 5 sessions of follicular aspiration with an interval of 45 days. In each aspiration session, 7.9 ± 0.7 oocytes were recovered per cow, with a recovery rate of 64.9% ± 0.5 and a rate of viable and non-viable oocytes of 64.3% ± 0.6 and 35.7% ± 0.7, respectively. A difference (P < 0.05) in oocyte quality was presented for grades I, II and III (7.7 ± 0.4, 19.8 ± 0.5 and 36.8 ± 0.5, respectively). The results suggest that Chino Santandereano cows submitted to the OPU technique have a higher percentage of grade III oocytes recovered.

A review of the reproductive system in anuran amphibians.

Reproductive biology is an important topic that is well explored in many vertebrates, but information about frogs' reproductive mechanisms could be improved. Therefore, this review aims to provide organized and specific information on frog reproduction. First, we developed schemes that illustrate the general information regarding reproductive biological mechanisms in frogs in a specific way. Then, we described the physiological, histological, and morphological mechanisms of each organ of the reproductive system of male and female frogs. Finally, this manuscript may contribute to a broader understanding of anuran reproductive biology. Since, understanding frogs' reproductive system permits one to make a comparison with reproduction with other anurans.

The role of L-carnitine in bovine embryo metabolism. A review of the effect of supplementation with a metabolic modulator on in vitro embryo production.

Early embryo development is driven first by the maternal RNAs and proteins accumulated during the oocyte's cytoplasmic maturation and then after the embryo genome activation. In mammalian cells, ATP generation occurs via oxidative pathways or by glycolysis, whereas in embryonic stem cells, the consumption of glucose, pyruvate, lipids, and amino acids results in ATP synthesis. Although the bovine embryo has energy reserves in glycogen and lipids, the glycogen concentration is deficient. Conversely, lipids represent the most abundant energy reservoir of bovine embryos, where lipid droplets-containing triacylglycerols are the main fatty acid stores. Oocytes of many mammalian species contain comparatively high amounts of lipids stored as droplets in the ooplasm. L-carnitine has been described as a cofactor that facilitates the mobilization of fatty acids present in the oocyte's cytoplasm into the mitochondria to facilitate ß-oxidation processes. However, the L-carnitine effects by addition to media in the in vitro produced embryos on the quality are highly disputed and contradictory by different researchers. This review's objective was to explore the effect that the addition of L-carnitine on culture media could have on the overall bovine embryo production in vitro, from the oocyte metabolism to the modulation of gene expression in the developing embryos.

Protein source in maturation media affects gene expression in cumulus cells and embryo development in cattle.

We aimed to evaluate if protein source (PS) alterations during IVM affect embryo sex/development and gene expression profile in cumulus cells (CCs). Bovine oocytes were matured and cultured in the presence of FBS or BSA. Then, the PS effect during IVM on gene expression (GPC4, VCAN, GHR, PTGS2, and ALCAM) was determined. CC biopsy was removed before and after IVM treatments. After fertilization and cultured, CCs were grouped according to their fate into CCs from immature COCs, CCs from COCs that did or did not result in embryos (according to PS). Results showed that when the culture was performed in FBS presence, blastocyst rate was higher (p < 0.05) than BSA. However, when embryos were cultured with BSA, no effect (p > 0.05) of PS during IVM was observed. PS used during IVM did not affect embryos sex (p > 0.05) but changed VCAN, GHR, PTGS2, and ALCAM genes expression. No differences (p > 0.05) were observed between immature and mature CCs groups in gene expression, regardless of their fate. Only the GHR gene was related to embryo production but just with FBS on IVM. In conclusion, PS can affect embryo development when using the serum on IVM and IVC, influences CCs gene expression, and has to be considered when studying oocyte quality markers.

Efeitos imediatos, tardios e transgeracionais do estresse térmico em gametas / Immediate, late and transgenerational effects of heat stress on gametes

As perdas de produtividade e fertilidade animal associadas ao estresse térmico durante os meses mais quentes do ano é um dos maiores desafios do setor pecuário. Na indústria de leite as perdas econômicas causadas pelo estresse térmico foram estimadas em mais de 1,5 bilhões de dólares por ano. No que tange a reprodução, já foi demonstrado que o estresse térmico exerce múltiplos efeitos deletérios, causando disfunções endócrinas e alterando a sequência orquestrada de eventos importantes para a gametogênese e para o desenvolvimento embrionário inicial. Estudos recentes têm esclarecido o padrão temporal no qual os danos são estabelecidos e carreados dependendo da intensidade do estresse. Enquanto os efeitos imediatos do estresse térmico nos gametas já são bem caracterizados, existem evidências de que alguns danos podem ser carreados de forma tardia e possivelmente entre gerações. Além disso, dados emergentes indicam que o estresse térmico compromete a reprogramação da metilação do DNA que ocorre durante a gametogênese e a programação do desenvolvimento in utero. Dessa forma, esse artigo visa explorar os efeitos imediatos, tardios e transgeracionais do estresse térmico nos gametas.(AU)

The drop on animal productivity and fertility associated with heat stress during the hot months of the year is one of the biggest challenges for the livestock sector. For the dairy industry the economic losses caused by heat stress have been estimated over 1.5 billion dollars per year. It has already been demonstrated that heat stress exerts multiple deleterious effects on reproductive function, causing endocrine dysfunctions as well as changes in the sequence of events required for gametogenesis and early embryonic development. Recent studies have shed a light in the temporal pattern in which heat-induced damage is established and carried forward depending on the intensity of stress. While the immediate effects of heat stress on gametes are well characterized, there is evidence that some damage can be carried over for longer periods and even across generations. Furthermore, emerging data indicate that heat stress compromises DNA methylation reprogramming that occurs during gametogenesis and developmental programming in utero. Thus, this paper aims to explore the immediate, late and transgenerational effects of heat stress on gametes.(AU)

Insulin-like growth factor-1 improves in vitro meiotic resumption of dromedary camel (Camelus Dromedarius) oocytes

Despite relatively high maturation rate of in vitro matured oocytes in the dromedary camel, however, blastocyst production is very low after in vitro fertilization (IVF). Herein, the influences of oocyte collection method (follicular aspiration vs slicing; Experiment I), the addition of Insulin-like growth factor I (IGF-I) to the maturation medium (Experiment II) on in vitro maturation (IVM) of oocyte were investigated. Although the nuclear maturation did not differ regardless of collecting method, follicular aspiration led to lower degeneration rates than those in controls (P < 0.05). The percentages of oocytes at MII were greater in the presence of IGF-1 than in its absence (71.9% vs 48.4%, respectively, P<0.05). Additionally, the percentages of degenerated oocytes were higher in the control group compared to oocytes cultured in the presence of IGF-I (23.6% vs 10.4%, respectively, P<0.05). IGF-I treatment improved the quality of MII matured oocytes as evidenced by the decrease of cathepsin B (CTSB) activity, a marker of poor quality oocytes, when compared to control ones (P < 0.05). In conclusion, follicular aspiration decreased the degeneration rate; however, it had no effect on completion of maturation. IGF-I enhanced the IVM of oocyte and decreased degeneration rate.(AU)

Factors affecting the in vitro embryo production in buffalo (Bubalus bubalis): A review.

Under natural and well-managed conditions, the buffalo has good reproductive and productive indices. However, in vitro embryo production (IVEP) has been used commercially to maximise the number of elite animals. In this species, several factors (donor management, in vitro culture medium, semen, in vitro conditions, embryo transfer) still affect the IVEP results. In addition, the cost of this technique is very high for this purpose. Therefore, more studies, as well as adequate plans, are needed to achieve this objective efficiently. In this review, we discussed the current commercial status, influencing factors (in vivo and in vitro), and the progress and future challenges of IVEP in buffalo. A total of 81 references were used from 1979 to 2022. The relevant data or literature were searched using the following databases: Google, ResearchGate, Science Alert, Science Direct and PubMed, using the following keywords: buffalo oocytes/COCs, buffalo embryos, pregnancy and calving or live birth rate after embryo transfer. The best maturation, cleavage and blastocyst rates in the in vitro production of buffalo embryos were 95.8, 75.2 and 33.4%, respectively. The pregnancy and live birth rates ranged from 22.2% to 43.5% and from 15.3% to 36.5%, respectively, after the transfer of fresh embryos produced in vitro to the recipients. This review will help to contextualise IVEP in buffaloes, as well as create an adequate plan for implementing IVEP in buffaloes.

Anti-Trypanosomal Bufadienolides from the Oocytes of the Toad Rhinella alata (Anura, Bufonidae).

Amphibians are widely known as a prolific source of bioactive metabolites. In this work, we isolated and characterized compounds with antiparasitic activity from the oocytes of the toad Rhinella alata collected in Panama. Bio-guided isolation and structural elucidation were carried out using chromatographic and spectroscopic techniques, respectively. The organic extract was subjected to solid phase extraction followed by HPLC purification of the fraction with in vitro activity against Trypanosoma cruzi trypomastigotes. Seven steroids (1-7) of the bufadienolide family were isolated, and their structures were determined using NMR and MS analyses; of these 19-formyl-dyscinobufotalin, (3) is reported as a new natural product. Compounds 1 and 3-7 resulted in a good anti-trypanosomal activity profile. Among these, 16ß-hydroxyl-hellebrigenin (1) and bufalin (7) showed significant selectivity values of >5 and 2.69, respectively, while the positive control benznidazole showed a selectivity of 18.81. Furthermore, molecular docking analysis showed compounds 1, 3 and 7 interact through H-bonds with the amino acid residues GLN-19, ASP-158, HIS-159 and TRP-177 from cruzipain at the catalytic site. Given the lack of therapeutic options to treat American trypanosomiasis, this work can serve as the basis for further studies that aim for the development of bufadienolides or their derivatives as drugs against Chagas disease.