Toxicologia reprodutiva de ratos adultos expostos ao 2,3,7,8-Tetraclorodibenzo-P-Dioxina (TCDD) in útero

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intrauterine exposure to diesel exhaust diminishes adult ovarian reserve

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da progesterona exógena na produção in vitro de embriões em novilhas Nelore pré-púberes

Pós-graduação em Medicina Veterinária - FCAV

Effect of adding a gonadotropin-releasing-hormone treatment at the beginning and a second prostaglandin F-2 alpha treatment at the end of an estradiol-based protocol for timed artificial insemination in lactating dairy cows during cool or hot seasons of the year

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Luteal changes after treatment with sub-luteolytic doses of prostaglandin (cloprostenol sodium) in cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Manifestation of estrous behavior and subsequent progesterone concentration at timed-embryo transfer in cattle are positively associated with pregnancy success of recipients

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estresse calórico sobre a luteólise de vacas holandesas não lactantes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Angiogênese, vascularização e uso do ultrassom Doppler colorido como ferramenta de avaliação das estruturas ovarianas

Angiogenesis occurs as a physiologic process and is essential for normal growth and development of tissue. The ovary and its structures need adequate vascular network to ensure the availability of oxygen, nutrients, hormones, substrate, and ensure the transfer of different hormones to target cells. Then, the proper formation of this network is a limiting step for the proper functioning of this organ in general. In recent years, the local blood flow of the ovary, has been examined by color Doppler ultrasound, being able to analyze the individual follicles and the corpus luteum. This review will board the relevant aspects of the restructuring vascular ovary during the estrous cycle in female domestic large.

Produção de progesterona pelas células luteínicas esteroidogênicas bovina cultivadas e co-cultivadas in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morfologia do útero e ovários de Artibeus planirostris (Phyllostomidae: Chiroptera) durante as fases do ciclo reprodutivo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biopsias luteais em vacas Nelore

The present study describes a technique to obtain consecutive luteal samples by colpotomy. The animals received an epidural anesthesia and local anesthesia (vaginal vault) and after ten minutes the vaginal vault was incised with a scalpel blade and tissue was dissected to provide access to the pelvic cavity and to retract the ovary into the vagina. Then, a luteal biopsy was performed with a Yomann biopsy nipper. Signs indicative of pain and stress during the vaginal vault incision, traction of ovary or luteal biopsy were observed only in two collections. However, these signs were observed in ten collections during dissection of the vaginal wall and peritoneum. The occurrence of ataxia was observed in 26 collections and it was usually related to a longer duration of the procedure. Ataxia could be divided in light (15/26), moderate (6/26) and severe (5/26). The occurrence of ovarian adhesions ipsilateral to the incision was evaluated only in the initial four collections. Adhesions were present in 16 collections. The protocol described above provided a safe and efficient method to acquire luteal samples. The low incidence of adhesions allows the consecutive use of females without any interference in subsequent ovulations and collections.

Atuação do interferon-tau no reconhecimento materno da gestação

Maternal recognition of pregnancy is a process by which the conceptus signals its presence to the mother in order to prolong the life of the corpus luteum (CL) thus maintaining the pregnancy. This process occurs between days 15 and 19 after fertilization and is the most important biological challenge for obtaining satisfactory reproductive indices in bovine. Interferon-tau (IFN-τ) glycoprotein -secreted in the uterus by the conceptus- has a paracrine action inhibiting the expression of estrogen receptors (ESR1) and oxytocin (OXTR) in the endometrium, thus preventing the release of luteolytic pulses of prostaglandin F2 alpha (PGF2α), hormone responsible for the onset of luteolysis. IFN-τ also increases the expression of several interferon-stimulated genes (ISGs) in the uterus, CL, and blood cells. Direct endocrine action of IFN-τ on extrauterine tissues stimulates ISGs expression, which in the corpus luteum seems to be involved with luteal resistance to luteolytic action of PGF2α. This review discusses recent findings on the luteolysis mechanism in the bovine and endocrine and paracrine mechanisms such as IFN-τ during the maternal recognition of pregnancy.

Dinâmica de corpos lúteos em protocolos com redução da dose de FSH na superovulação em ovelhas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Direct effect of PGF2 alpha pulses on PRL pulses, based on inhibition of PRL or PGF2 alpha secretion in heifers

The relationships between PRL and PGF(2 alpha) and their effect on luteolysis were studied. Heifers were treated with a dopamine-receptor agonist (bromocriptine; Bc) and a Cox-1 and -2 inhibitor (flunixin meglumine [FM]) to inhibit PRL and PGF(2 alpha), respectively. The Bc was given (Hour 0) when ongoing luteolysis was indicated by a 12.5% reduction in CL area (cm(2)) from the area on Day 14 postovulation, and FM was given at Hours 0, 4, and 8. Blood samples were collected every 8-h beginning on Day 14 until Hour 48 and hourly for Hours 0 to 12. Three groups of heifers in ongoing luteolysis were used: control (n = 7), Bc (n = 7), and FM (n = 4). Treatment with Bc decreased (P < 0.003) the PRL concentrations averaged over Hours 1 to 12. During the greatest decrease in PRL (Hours 2-6), LH concentrations were increased. Progesterone concentrations averaged over hours were greater (P < 0.05) in the Bc group than in the controls. In the FM group, no PGFM pulses were detected, and PRL concentrations were reduced. Concentrations of PGFM were not reduced in the Bc group, despite the reduction in PRL. Results supported the hypothesis that a decrease (12.5%) in CL area (cm(2)) is more efficient in targeting ongoing luteolysis (63%) than using any day from Days 14 to >= 19 (efficiency/day, 10-24%). The hypothesis that PRL has a role in luteolysis was supported but was confounded by the known positive effect of LH on progesterone. The hypothesis was supported that the synchrony of PGFM and PRL pulses represents a positive effect of PGF(2 alpha), on PRL, rather than an effect of PRL on PGF(2 alpha). (C) 2012 Elsevier Inc. All rights reserved.

Potencial envolvimento da adiponectina e seus receptores na modulação da esteroidogênese em corpo lúteo de cadelas ao longo do diestro

No ciclo estral de cadelas a fase luteínica, denominada diestro, compreende um período que varia de 60 a 100 dias em animais não-prenhes, caracterizado pela elevação plasmática de progesterona nos primeiros 20 dias pós ovulação (p.o). A adiponectina é a mais abundante proteína secretada pelo tecido adiposo, porém sua concentração plasmática diminui significativamente em alterações metabólicas como resistência insulínica e Diabetes mellitus tipo2, alterações descritas como relacionadas em algumas cadelas com o período de diestro. O objetivo do estudo foi determinar a expressão e imunolocalização do sistema adiponectina (adiponectina e seus receptores, adipoR1 e adipoR2) no corpo lúteo de cadelas ao longo do diestro, correlacionando-o ao perfil hormonal de 17β-estradiol e progesterona, assim como à expressão de um dos genes alvo do sistema, o PPAR-γ. Para realização do estudo foram coletados corpos lúteos de 28 cadelas durante ovariosalpingohisterectomia de eleição nos dias 10, 20, 30, 40, 50, 60 e 70 pós ovulação (o dia zero da ovulação foi considerado aquele no qual a concentração plasmática de progesterona atingiu 5ng/mL). Os corpos lúteos foram avaliados por imunohistoquímica para adiponectina e seus receptores e a expressão do RNAm do PPAR-γ por PCR em tempo real. A análise estatística da avaliação gênica foi realizada com o teste ANOVA, seguido por comparação múltipla Newman-Keuls. O sinal da adiponectina apresentou-se mais intenso até os primeiros 20 dias p.o, momento de regência da progesterona; houve queda gradativa após este período, coincidindo com a ascensão do 17β-estradiol, cujo pico foi notado próximo do dia 40 p.o. A queda marcante da adiponectina ocorreu após 50 dias p.o. O sinal do adipoR1 mostrou-se bem evidente até os 40 dias p.o e o do adipoR2 até os 50 dias p. o, decaindo posteriormente. Foi observada maior expressão do gene PPAR-γ aos 10, 30 e 70 dias p.o. Estes resultados mostram que a expressão protéica da adiponectina e de seus receptores se altera ao longo do diestro e que estas alterações podem estar relacionados às alterações hormonais e expressão do PPAR- γ, participando do mecanismo fisiológico de desenvolvimento, manutenção, atividade e regressão luteínica em cadelas.