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1.
Sci Rep ; 13(1): 22355, 2023 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-38102304

RESUMO

The African naked mole-rat (Heterocephalus glaber) is an attractive model for cancer and aging research due to its peculiar biological traits, such as unusual long life span and resistance to cancer. The establishment of induced pluripotent stem cells (iPSCs) would be a useful tool for in vitro studies but, in this species, the reprogramming of somatic cells is problematic because of their stable epigenome. Therefore, an alternative approach is the derivation of embryonic stem cells from in vitro-produced embryos. In this study, immature oocytes, opportunistically retrieved from sexually inactive females, underwent first in vitro maturation (IVM) and then in vitro fertilization via piezo-intracytoplasmic sperm injection (ICSI). Injected oocytes were then cultivated with two different approaches: (i) in an in vitro culture and (ii) in an isolated mouse oviduct organ culture system. The second approach led to the development of blastocysts, which were fixed and stained for further analysis.


Assuntos
Neoplasias , Injeções de Esperma Intracitoplásmicas , Animais , Feminino , Masculino , Camundongos , Blastocisto , Fertilização in vitro , Oócitos , Sêmen , Ratos-Toupeira
2.
Front Immunol ; 14: 1172467, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37153552

RESUMO

The naked mole-rat (NMR) is a unique long-lived rodent which is highly resistant to age-associated disorders and cancer. The immune system of NMR possesses a distinct cellular composition with the prevalence of myeloid cells. Thus, the detailed phenotypical and functional assessment of NMR myeloid cell compartment may uncover novel mechanisms of immunoregulation and healthy aging. In this study gene expression signatures, reactive nitrogen species and cytokine production, as well as metabolic activity of classically (M1) and alternatively (M2) activated NMR bone marrow-derived macrophages (BMDM) were examined. Polarization of NMR macrophages under pro-inflammatory conditions led to expected M1 phenotype characterized by increased pro-inflammatory gene expression, cytokine production and aerobic glycolysis, but paralleled by reduced production of nitric oxide (NO). Under systemic LPS-induced inflammatory conditions NO production also was not detected in NMR blood monocytes. Altogether, our results indicate that NMR macrophages are capable of transcriptional and metabolic reprogramming under polarizing stimuli, however, NMR M1 possesses species-specific signatures as compared to murine M1, implicating distinct adaptations in NMR immune system.


Assuntos
Citocinas , Macrófagos , Camundongos , Animais , Fenótipo , Citocinas/metabolismo , Ratos-Toupeira
3.
Front Vet Sci ; 8: 657284, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34277752

RESUMO

Despite a profound knowledge on reproduction biology in greater one-horned (GOH) rhinoceros, many individuals cope with sub or infertility or an-ovulatory estrous. At the same time, early and regular captive breeding is of high importance in female GOH rhinoceros due to their high prevalence to develop genital tract tumors with consequent cessation of reproduction. Thus, mature, an-ovulatory GOH rhinoceros represent a challenge for captive breeding programs and warrant for means of reliable ovulation induction. Here, we used hCG and GnRH analog histrelin to induce ovulation in an-ovulatory GOH rhinoceros. Upon ultrasound diagnosis of a preovulatory follicle hCG or GnRH were injected to induce ovulation (n = 11). As a result, 75% of the hCG (n = 6/8) and 33% of GnRH (n = 1/3) inductions resulted in ovulation. Ovulation occurred when fecal estrogen concentration increased before and pregnane concentration after induction. Thirty-six percent of all treatments (n = 4/11) failed to induce ovulation. When ovulation induction by hCG/GnRH injection failed, estrogen and pregnane concentrations were significantly lower compared to ovulatory estrous (P < 0.001). Our results suggest that hCG and GnRH analog facilitate an easily applicable treatment to induce ovulation in females with behavioral but at times an-ovulatory estrous. Frequent use of hCG as an ovulation inducer might help to achieve pregnancies in genetically important but an-ovulatory GOH rhinoceroses.

4.
Front Mol Biosci ; 8: 660959, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34079817

RESUMO

Most research on mechanisms of aging is being conducted in a very limited number of classical model species, i.e., laboratory mouse (Mus musculus), rat (Rattus norvegicus domestica), the common fruit fly (Drosophila melanogaster) and roundworm (Caenorhabditis elegans). The obvious advantages of using these models are access to resources such as strains with known genetic properties, high-quality genomic and transcriptomic sequencing data, versatile experimental manipulation capabilities including well-established genome editing tools, as well as extensive experience in husbandry. However, this approach may introduce interpretation biases due to the specific characteristics of the investigated species, which may lead to inappropriate, or even false, generalization. For example, it is still unclear to what extent knowledge of aging mechanisms gained in short-lived model organisms is transferable to long-lived species such as humans. In addition, other specific adaptations favoring a long and healthy life from the immense evolutionary toolbox may be entirely missed. In this review, we summarize the specific characteristics of emerging animal models that have attracted the attention of gerontologists, we provide an overview of the available data and resources related to these models, and we summarize important insights gained from them in recent years. The models presented include short-lived ones such as killifish (Nothobranchius furzeri), long-lived ones such as primates (Callithrix jacchus, Cebus imitator, Macaca mulatta), bathyergid mole-rats (Heterocephalus glaber, Fukomys spp.), bats (Myotis spp.), birds, olms (Proteus anguinus), turtles, greenland sharks, bivalves (Arctica islandica), and potentially non-aging ones such as Hydra and Planaria.

5.
Cells ; 10(3)2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668197

RESUMO

The bioactivity of the IGF system is not a function of isolated hormone concentrations in a given biological matrix. Instead, the biological activities of IGFs are regulated by IGFBPs, IGFBP proteases, and inhibitors of IGFBP proteases. Therefore, assays based on IGF-related bioactivity may describe functions of the complete IGF system in a given biological matrix. Of particular interest are the IGF system effects on the AKT/mTOR pathway, as a dominant system for controlling growth, metabolism, and aging. In order to improve the sensitivity of IGF-dependent bioactivity, we made use of the known short-term and enhancing effects of IGFBP2 on the intracellular PI3K pathway. As a specific readout of this pathway, and further as a marker of the mTOR pathway, we assessed the phosphorylation of AKT-Ser473. Preincubation using IGFBP2 enhanced IGF1-dependent AKT-Ser473 phosphorylation in our experimental system. The assay's specificity was demonstrated by inhibition of IGF1 receptors outside or inside the cell, using antiserum or small molecule inhibitors, which reduced AKT phosphorylation in response to exogenous IGF1 (p < 0.05). The maximal response of AKT phosphorylation was recorded 15 to 60 min after the addition of IGF1 to cell monolayers (p < 0.001). In our cellular system, insulin induced AKT phosphorylation only at supra-physiological concentrations (µM). Using this novel assay, we identified the differential biological activity of the IGF system in AKT-Ser473 phosphorylation in serum (mouse, naked mole rat, and human), in cerebrospinal fluid (human), and in colostrum or mature milk samples (dairy cow). We have developed a sensitive and robust bioassay to assess the IGF-related activation of the AKT/mTOR pathway. The assay works efficiently and does not require expensive cell culture systems. By using capillary immuno-electrophoresis, the readout of IGF-related bioactivity is substantially accelerated, requiring a minimum of hands-on time. Importantly, the assay system is useful for studying IGF-related activity in the AKT/mTOR pathway in a broad range of biological matrices.


Assuntos
Bioensaio/métodos , Fator de Crescimento Insulin-Like I/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Técnicas de Cultura de Células , Humanos , Transdução de Sinais
6.
Biol Rev Camb Philos Soc ; 96(2): 376-393, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33128331

RESUMO

Naked mole-rats express many unusual traits for such a small rodent. Their morphology, social behaviour, physiology, and ageing have been well studied over the past half-century. Many early findings and speculations about this subterranean species persist in the literature, although some have been repeatedly questioned or refuted. While the popularity of this species as a natural-history curiosity, and oversimplified story-telling in science journalism, might have fuelled the perpetuation of such misconceptions, an accurate understanding of their biology is especially important for this new biomedical model organism. We review 28 of these persistent myths about naked mole-rat sensory abilities, ecophysiology, social behaviour, development and ageing, and where possible we explain how these misunderstandings came about.


Assuntos
Ratos-Toupeira , Comportamento Social , Envelhecimento , Animais , Biologia
7.
Theriogenology ; 156: 181-188, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32755717

RESUMO

In captive rhinoceros stillbirth and perinatal death are recorded at a rate of 6-17% in the various species. At the same time there is a substantial lack of knowledge on rhinoceros parturition. Yet, predicting parameters for birth and progress of parturition are fundamental for the recognition of dystocia and perinatal problems. Therefore, we here intended to pay close attention to the Achilles heel of the 1.5-2.5 year reproduction cycle in rhinoceros, the parturition. For the prediction of parturition we recorded timelines for pre-birth udder development, genital swelling, milk production, behavioral unrest, and decrease of serum progesterone concentration and the gestational length in 19 white rhinoceros. First, second and third labour stage, foetal presentation and events in perinatal period were recorded to describe normal parturition and establish a guideline for better birth management in rhinoceros. Udder development and genital swelling were observed 3 and 2 weeks prior birth, respectively. Milk production was observed to start up to 3 weeks prior birth and increased significantly in the last week with most significant increase one day before parturition to 50.6 ± 45.4 mL (p < 0.006). Serum progesterone concentration started to decrease 7 days prior parturition and more significantly 48 h before parturition. While behavioral unrest and first stage labour was not observed reliably in all females the break of foetal waters and thus the start of second stage labour was unmistakably observed. Second stage labour, when foetal membranes had ruptured until the foetus was born, took 1:50 ± 0:20 h:min. Eighty-four percent of fetuses were born in anterior presentation (n = 16/19) and the final expulsion took <25 min suggesting that this is the normal presentation in white rhinoceros. In the less frequent posterior presentation final expulsion took up to 47 min. Overall, 95% of calves were born alive. Calves were standing and nursing in 0:55 ± 0:12 min and 3:32 ± 0:53 h:min, respectively. In 10.5% of births (n = 2/19) in anterior presentation perinatal complications occurred. Stillbirth occurred once (5.3% n = 1/19) when the foetus was born in posterior presentation. The recorded gestational length was 506 ± 2d. Delivering live offspring is of key importance to establish a new generation and secure long-term survival of a species. Various pre-birth changes, significant decrease of serum progesterone 48 h prior birth, different labour stages, foetal presentation and perinatal events described here add substantial knowledge on the understanding of normal rhinoceros parturition and may help diagnose dystocia and perinatal complications.


Assuntos
Distocia , Trabalho de Parto , Animais , Distocia/veterinária , Feminino , Parto , Perissodáctilos , Gravidez , Natimorto/veterinária
8.
Proc Natl Acad Sci U S A ; 117(12): 6491-6501, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32152094

RESUMO

The mitochondria of various tissues from mice, naked mole rats (NMRs), and bats possess two mechanistically similar systems to prevent the generation of mitochondrial reactive oxygen species (mROS): hexokinases I and II and creatine kinase bound to mitochondrial membranes. Both systems operate in a manner such that one of the kinase substrates (mitochondrial ATP) is electrophoretically transported by the ATP/ADP antiporter to the catalytic site of bound hexokinase or bound creatine kinase without ATP dilution in the cytosol. One of the kinase reaction products, ADP, is transported back to the mitochondrial matrix via the antiporter, again through an electrophoretic process without cytosol dilution. The system in question continuously supports H+-ATP synthase with ADP until glucose or creatine is available. Under these conditions, the membrane potential, ∆ψ, is maintained at a lower than maximal level (i.e., mild depolarization of mitochondria). This ∆ψ decrease is sufficient to completely inhibit mROS generation. In 2.5-y-old mice, mild depolarization disappears in the skeletal muscles, diaphragm, heart, spleen, and brain and partially in the lung and kidney. This age-dependent decrease in the levels of bound kinases is not observed in NMRs and bats for many years. As a result, ROS-mediated protein damage, which is substantial during the aging of short-lived mice, is stabilized at low levels during the aging of long-lived NMRs and bats. It is suggested that this mitochondrial mild depolarization is a crucial component of the mitochondrial anti-aging system.


Assuntos
Envelhecimento , Mitocôndrias/fisiologia , Membranas Mitocondriais/fisiologia , Difosfato de Adenosina/metabolismo , Animais , Quirópteros , Creatina/metabolismo , Transporte de Elétrons , Embrião de Mamíferos , Glucose/metabolismo , Hexoquinase/metabolismo , Potencial da Membrana Mitocondrial , Camundongos , Mitocôndrias/metabolismo , Membranas Mitocondriais/enzimologia , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Ratos-Toupeira , Especificidade de Órgãos , Espécies Reativas de Oxigênio/metabolismo , Especificidade da Espécie
9.
Physiol Rev ; 97(2): 699-720, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28202600

RESUMO

It has been suggested that highly social mammals, such as naked mole rats and humans, are long-lived due to neoteny (the prolongation of youth). In both species, aging cannot operate as a mechanism facilitating natural selection because the pressure of this selection is strongly reduced due to 1) a specific social structure where only the "queen" and her "husband(s)" are involved in reproduction (naked mole rats) or 2) substituting fast technological progress for slow biological evolution (humans). Lists of numerous traits of youth that do not disappear with age in naked mole rats and humans are presented and discussed. A high resistance of naked mole rats to cancer, diabetes, cardiovascular and brain diseases, and many infections explains why their mortality rate is very low and almost age-independent and why their lifespan is more than 30 years, versus 3 years in mice. In young humans, curves of mortality versus age start at extremely low values. However, in the elderly, human mortality strongly increases. High mortality rates in other primates are observed at much younger ages than in humans. The inhibition of the aging process in humans by specific drugs seems to be a promising approach to prolong our healthspan. This might be a way to retard aging, which is already partially accomplished via the natural physiological phenomenon neoteny.


Assuntos
Envelhecimento/fisiologia , Hominidae/metabolismo , Longevidade/fisiologia , Neoplasias/metabolismo , Estresse Oxidativo/fisiologia , Animais , Evolução Biológica , Humanos
10.
Toxicology ; 366-367: 60-7, 2016 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-27452193

RESUMO

Estrogens are important for the bone development and health. Exposure to endocrine disrupting chemicals during the early development has been shown to affect the bone phenotype later in life. Several studies have been performed in rodents, while in larger animals that are important to bridge the gap to humans there is a paucity of data. To this end, the pig as large animal model was used in the present study to assess the influence of gestational estradiol-17ß (E2) exposure on the bone development of the prepubertal and adult offspring. Two low doses (0.05 and 10µg E2/kg body weight) referring to the 'acceptable daily intake' (ADI) and the 'no observed effect level' (NOEL) as stated for humans, and a high-dose (1000µg E2/kg body weight), respectively, were fed to the sows every day from insemination until delivery. In the male prepubertal offspring, the ADI dose group had a lower strength strain index (p=0.002) at the proximal tibia compared to controls, which was determined by peripheral quantitative computed tomography. Prepubertal females were not significantly affected. However, there was a higher cortical cross-sectional area (CSA) (p=0.03) and total CSA (p=0.02) at the femur midpoint in the adult female offspring of the NOEL dose group as measured by computed tomography. These effects were independent from plasma hormone concentrations (leptin, IGF1, estrogens), which remained unaltered. Overall, sex-specific effects on bone development and non-monotonic dose responses were observed. These results substantiate the high sensitivity of developing organisms to exogenous estrogens.


Assuntos
Desenvolvimento Ósseo/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Estradiol/toxicidade , Efeitos Tardios da Exposição Pré-Natal/patologia , Fatores Sexuais , Animais , Animais Recém-Nascidos , Peso Corporal , Densidade Óssea/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Disruptores Endócrinos/administração & dosagem , Estradiol/administração & dosagem , Feminino , Fêmur/efeitos dos fármacos , Masculino , Nível de Efeito Adverso não Observado , Gravidez , Suínos , Tíbia/efeitos dos fármacos
11.
PLoS One ; 10(6): e0130470, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26103567

RESUMO

BACKGROUND: The naked mole-rat (NMR) is a long-lived and cancer resistant species. Identification of potential anti-cancer and age related mechanisms is of great interest and makes this species eminent to investigate anti-cancer strategies and understand aging mechanisms. Since it is known that the NMR expresses higher liver mRNA-levels of alpha 2-macroglobulin than mice, nothing is known about its structure, functionality or expression level in the NMR compared to the human A2M. RESULTS: Here we show a comprehensive analysis of NMR- and human plasma-A2M, showing a different prediction in glycosylation of NMR-A2M, which results in a higher molecular weight compared to human A2M. Additionally, we found a higher concentration of A2M (8.3±0.44 mg/mL vs. and 4.4±0.20 mg/mL) and a lower total plasma protein content (38.7±1.79 mg/mL vs. 61.7±3.20 mg/mL) in NMR compared to human. NMR-A2M can be transformed by methylamine and trypsin resulting in a conformational change similar to human A2M. NMR-A2M is detectable by a polyclonal antibody against human A2M. Determination of tryptic and anti-tryptic activity of NMR and human plasma revealed a higher anti-tryptic activity of the NMR plasma. On the other hand, less proteolytic activity was found in NMR plasma compared to human plasma. CONCLUSION: We found transformed NMR-A2M binding to its specific receptor LRP1. We could demonstrate lower protein expression of LRP1 in the NMR liver tissue compared to human but higher expression of A2M. This was accompanied by a higher EpCAM protein expression as central adhesion molecule in cancer progression. NMR-plasma was capable to increase the adhesion in human fibroblast in vitro most probably by increasing CD29 protein expression. This is the first report, demonstrating similarities as well as distinct differences between A2M in NMR and human plasma. This might be directly linked to the intriguing phenotype of the NMR and suggests that A2M might probably play an important role in anti-cancer and the anti-aging mechanisms in the NMR.


Assuntos
Neoplasias/sangue , alfa-Macroglobulinas/metabolismo , Animais , Moléculas de Adesão Celular/metabolismo , Humanos , Ratos-Toupeira , Filogenia
12.
PLoS One ; 9(3): e90469, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24599348

RESUMO

Felids generally follow a poly-estrous reproductive strategy. Eurasian lynx (Lynx lynx) display a different pattern of reproductive cyclicity where physiologically persistent corpora lutea (CLs) induce a mono-estrous condition which results in highly seasonal reproduction. The present study was based around a sono-morphological and endocrine study of captive Eurasian lynx, and a control-study on free-ranging lynx. We verified that CLs persist after pregnancy and pseudo-pregnancy for at least a two-year period. We could show that lynx are able to enter estrus in the following year, while CLs from the previous years persisted in structure and only temporarily reduced their function for the period of estrus onset or birth, which is unique among felids. The almost constant luteal progesterone secretion (average of 5 ng/ml serum) seems to prevent folliculogenesis outside the breeding season and has converted a poly-estrous general felid cycle into a mono-estrous cycle specific for lynx. The hormonal regulation mechanism which causes lynx to have the longest CL lifespan amongst mammals remains unclear. The described non-felid like ovarian physiology appears to be a remarkably non-plastic system. The lynx's reproductive ability to adapt to environmental and anthropogenic changes needs further investigation.


Assuntos
Corpo Lúteo/fisiologia , Estro/fisiologia , Lynx/fisiologia , Animais , Corpo Lúteo/diagnóstico por imagem , Manutenção do Corpo Lúteo/sangue , Estrogênios/sangue , Feminino , Estudos Longitudinais , Gravidez , Prostaglandinas/sangue , Reprodutibilidade dos Testes , Estações do Ano , Ultrassonografia
13.
PLoS One ; 9(3): e92595, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24671211

RESUMO

In Indian rhinoceros, extensive leiomyoma, a benign smooth muscle tumour, was sporadically diagnosed post mortem and commonly thought of as contributing factor for reduced fecundity of this species in captivity. However, to date, the prevalence of reproductive tract tumours and their relevance for fecundity are unknown. Our analysis of the international studbook now reveals that females cease reproducing at the age of 18.1±1.2 years; equivalent to a reproductive lifespan of just 9.5±1.3 years. This short reproductive life is in sharp contrast to their longevity in captivity of over 40 years. Here we show, after examining 42% of the captive female population, that age-related genital tract tumours are highly prevalent in this endangered species. Growth and development of these tumours was found to be age-related, starting from the age of 10 years. All females older than 12 years had developed genital tumours, just 7-9 years past maturity. Tumour sizes ranged from 1.5-10 cm. With age, tumours became more numerous, sometimes merging into one large diffuse tumour mass. These tumours, primarily vaginal and cervical, presumably cause widespread young-age infertility by the age of 18 years. In few cases, tumour necrosis suggested possible malignancy of tumours. Possible consequences of such genital tract tumour infestation are hindered intromission, pain during mating, hampered sperm passage, risk of ascending infection during pregnancy, dystocia, or chronic vaginal bleeding. In humans, leiomyoma affect up to 80% of pre-menopause women. While a leading cause for infertility, pregnancy is known to reduce the risk of tumour development. However, different from human, surgical intervention is not a viable treatment option in rhinoceroses. Thus, in analogy to humans, we suggest early onset and seamless consecutive pregnancies to help reduce prevalence of this disease, better maintain a self-sustained captive population and improve animal welfare.


Assuntos
Neoplasias dos Genitais Femininos/patologia , Reprodução , Animais , Cruzamento , Feminino , Fertilidade , Neoplasias dos Genitais Femininos/diagnóstico por imagem , Neoplasias dos Genitais Femininos/epidemiologia , Incidência , Perissodáctilos , Ultrassonografia
14.
Sci Rep ; 3: 1458, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23492830

RESUMO

Marsupials have a functional placenta for a shorter period of time compared to that of eutherian species, and their altricial young reach the teats without any help from the mother. We have monitored the short intrauterine development of one marsupial, the tammar wallaby, with high-resolution ultrasound from reactivation of the 100-cell diapausing blastocyst to birth. The expanding blastocyst could be visualized when it had reached a diameter of 1.5 mm. From at least halfway through pregnancy, there are strong undulating movements of the endometrium that massage the expanding vesicle against the highly secretory endometrial surface. These unique movements possibly enhance exchange of uterine secretions and gases between the mother and embryo. There was a constant rate of development measured ultrasonographically from mid-gestation, regardless of when the blastocyst reactivated. Interestingly climbing movements by the fetus began in utero about 3 days before birth, mimicking those required to climb to the pouch.


Assuntos
Blastocisto/fisiologia , Endométrio/fisiologia , Macropodidae/fisiologia , Placenta/fisiologia , Animais , Embrião de Mamíferos/diagnóstico por imagem , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/fisiologia , Endométrio/diagnóstico por imagem , Endométrio/embriologia , Feminino , Feto/embriologia , Feto/fisiologia , Macropodidae/embriologia , Placenta/diagnóstico por imagem , Placenta/embriologia , Gravidez , Fatores de Tempo , Ultrassonografia Pré-Natal
15.
Biol Reprod ; 85(4): 714-20, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21677310

RESUMO

Elephants express two luteinizing hormone (LH) peaks timed 3 wk apart during the follicular phase. This is in marked contrast with the classic mammalian estrous cycle model with its single, ovulation-inducing LH peak. It is not clear why ovulation and a rise in progesterone only occur after the second LH peak in elephants. However, by combining ovarian ultrasound and hormone measurements in five Asian elephants (Elephas maximus), we have found a novel strategy for dominant follicle selection and luteal tissue accumulation. Two distinct waves of follicles develop during the follicular phase, each of which is terminated by an LH peak. At the first (anovulatory) LH surge, the largest follicles measure between 10 and 19.0 mm. At 7 ± 2.4 days before the second (ovulatory) LH surge, luteinization of these large follicles occurs. Simultaneously with luteinized follicle (LUF) formation, immunoreactive (ir) inhibin concentrations rise and stay elevated for 41.8 ± 5.8 days after ovulation and the subsequent rise in progesterone. We have found a significant relationship between LUF diameter and serum ir-inhibin level (r(2) = 0.82, P < 0.001). The results indicate that circulating ir-inhibin concentrations are derived from the luteinized granulosa cells of LUFs. Therefore, it appears that the development of LUFs is a precondition for inhibin secretion, which in turn impacts the selection of the ovulatory follicle. Only now, a single dominant follicle may deviate from the second follicular wave and ovulate after the second LH peak. Thus, elephants have evolved a different strategy for corpus luteum formation and selection of the ovulatory follicle as compared with other mammals.


Assuntos
Elefantes/fisiologia , Inibinas/metabolismo , Luteinização/sangue , Hormônio Luteinizante/sangue , Folículo Ovariano/fisiologia , Detecção da Ovulação/veterinária , Animais , Corpo Lúteo/fisiologia , Ciclo Estral/sangue , Feminino , Fase Folicular/sangue , Células da Granulosa/metabolismo , Inibinas/sangue , Tamanho do Órgão , Folículo Ovariano/anatomia & histologia , Ovário/diagnóstico por imagem , Progesterona/sangue , Progesterona/metabolismo , Ultrassonografia
16.
Reprod Fertil Dev ; 22(7): 1159-65, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20797354

RESUMO

Early embryonic resorption or fetal loss is known to occur occasionally in captive elephants; however, this has mostly been reported anecdotally. The present study documents the case of a 24-year-old, multiparous Asian elephant cow that suffered embryonic death and resorption at around 18 weeks of gestation. From ovulation onwards, this female was sonographically examined 58 times. Blood was collected twice weekly for progestagen determination via enzyme immunoassay. On Day 42 after ovulation, a small quantity of fluid was detected in the uterine horn, which typically indicates the presence of a developing conceptus. Repeated inspections followed what appeared to be a normal pregnancy until Day 116. However, on Day 124, signs of embryonic life were absent. Progestagen concentrations started declining two weeks later, reaching baseline levels one month after embryonic death. Retrospectively, ultrasound examination revealed several abnormalities in the uterine horn. Besides an existing leiomyoma, multiple small cystic structures had formed in the endometrium at the implantation site and later in the placenta. These pathological findings were considered as possible contributors to the early pregnancy failure. PCR for endotheliotropic elephant herpes virus (EEHV) (which had occurred previously in the herd) as well as serology for other infectious organisms known to cause abortion in domestic animals did not yield any positive results. Although no definitive reason was found for this pregnancy to abort, this ultrasonographically and endocrinologically documented study of an early pregnancy loss provides important insights into the resorption process in Asian elephants.


Assuntos
Elefantes/fisiologia , Morte Fetal/veterinária , Ultrassonografia Pré-Natal/veterinária , Animais , Feminino , Morte Fetal/diagnóstico por imagem , Morte Fetal/fisiopatologia , Gravidez , Progesterona/sangue
17.
Biol Reprod ; 81(5): 989-95, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19587331

RESUMO

Fecal and urinary progestin analyses have shown that giraffes express a short reproductive cycle, averaging 15 days, compared with other large ruminants. However, actual ovarian events have not been correlated with the hormonal pattern. In this study, mature cycling female Rothschild giraffes (Giraffa camelopardalis rothschildi) were repeatedly examined by transrectal ultrasonography to correlate ovarian function with changes in fecal progestin (fP4 [n(c) = 6]) and estradiol (fE2 [n(c) = 6]) and serum progestin (n(c) = 2) as measured by enzyme immunoassay. Five females became pregnant and were monitored during early gestation. In this study, we discovered that hormone values for fP4 in cycling giraffes do not correlate with the classic profile of follicular development, ovulation, and luteogenesis. The corpus luteum (CL) and the next dominant follicle were forming simultaneously. A mean +/- SD peak in fE2 of 254.92 +/- 194.76 ng/g and subsequent ovulation occurred as early as 1 day after the fall in fP4. In pregnant giraffes, the CL reached a diameter significantly larger (mean +/- SD, 41.02 +/- 2.70 mm; P = 0.0126) than that during the cycle (33.48 +/- 2.80 mm), while follicular activity and fluctuating fE2 were still present. With this research, we demonstrated that the progesterone profile typically used to characterize the ovarian cycle does not correlate with luteal development in the ovaries of this species. Furthermore, we conclude that the giraffe could have evolved a short reproductive cycle because of the almost parallel order of ovarian events.


Assuntos
Estradiol/análise , Ciclo Estral/fisiologia , Fezes/química , Ovário/diagnóstico por imagem , Prenhez , Progestinas/análise , Ruminantes/fisiologia , Animais , Feminino , Imunoensaio , Ovário/fisiologia , Ovulação/sangue , Gravidez , Fatores de Tempo , Ultrassonografia
18.
Am J Primatol ; 69(11): 1278-84, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17440965

RESUMO

To simplify the procedure for superovulation in the rhesus monkey, this study was designed using polyvinylpyrrolidone (PVP) solution as a solvent for gonadotropins. Thirty-five cycling females (aged 5-8 years old) were divided into six groups during the breeding season (November- February). The groups were as follows: Group I, animals received twice-daily 35 IU recombinant human follicle-stimulating hormone (rhFSH) dissolved in 0.5 ml saline for 8 days as the control; Groups II and III, animals received single-daily 35 IU and 17 IU rhFSH in 0.5 saline, respectively, for 9 days; Groups IV, V and VI, received single-daily injection of 35 IU rhFSH, 17 IU rhFSH and 8.5 IU rhFSH dissolved in 0.5 ml 30% PVP (w/v) solution, respectively, for 9 days. After human chorionic gonadotropin was administered to induce the nuclear maturation of oocytes, oocytes were retrieved and the development competence of recovered oocytes treated with in vitro fertilization were observed. The plasma concentrations of follicle-stimulating hormone and ovarian responses were monitored during the treatment. The results showed that the number of recovered oocytes and the in vitro developmental competence of mature oocytes was equivalent among monkeys when treated with a single-daily treatment of 17 and 35 IU rhFSH with PVP preparation in Groups IV and V compared with the twice-daily 35 IU rhFSH treatments received by Group I. However, almost all animals in Groups II, III and VI responded poorly to corresponding stimulations. These findings indicate that a single-daily low dose of rhFSH dissolved in PVP solution can induce the satisfactory ovarian responses in rhesus monkeys. This has the potential to reduce treatment distress, stress to the animals, the labor of the operator as well as the amount of rhFSH used in ovarian stimulation, compared with traditional superovulation methods.


Assuntos
Hormônio Foliculoestimulante/administração & dosagem , Macaca mulatta/fisiologia , Indução da Ovulação/veterinária , Povidona , Superovulação , Animais , Feminino , Hormônio Foliculoestimulante/sangue , Indução da Ovulação/métodos , Proteínas Recombinantes/administração & dosagem , Soluções
19.
J Zoo Wildl Med ; 37(2): 202-5, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17312803

RESUMO

Transvaginal laparoscopy to allow assessment of ovarian pathology and to attempt retrieval of oocytes was facilitated in a captive, female black rhinoceros (Diceros bicornis minor) through the use of a sling on two separate occasions. Following induction of anesthesia with an opioid-based combination, the rhinoceros was intubated and maintained on isoflurane in oxygen. The use of the sling and volume controlled inhalation anesthesia allowed for maintenance of appropriate anatomic positioning, analgesia, and insufflation of the abdominal cavity for laparoscopy during both procedures.


Assuntos
Anestesia por Inalação/veterinária , Laparoscopia/veterinária , Perissodáctilos/fisiologia , Anestesia por Inalação/métodos , Animais , Animais de Zoológico , Conservação dos Recursos Naturais , Feminino , Laparoscopia/métodos
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