EXPRESSÃO DAS MAPKs EM FOLÍCULOS OVARIANOS E CORPOS LUTEOS EM DIFERENTES FASES DO CICLO ESTRAL DE BOVINOS

• Autor(a) principal: FERREIRA, Mônica Rodrigues
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/1194
• topic: MEK 1/2; ERK 1/2; foliculogênese; luteólise; Bovinos Ciclo estral 2. Folículos ovarianos Bovinos 3. Luteólise; MEK 1/2; ERK 1/2; folliculogenesis; luteolysis; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::PATOLOGIA ANIMAL::PATOLOGIA CLINICA ANIMAL

Bovine estrous cycle activates the pathways of MAPKs (mitogen activated protein) via oscillation of hypothalamus-pituitary-gonad axis hormones. The objective of this work was to evaluate in vivo the frequency of expression of active (phosphorylated) form, of p-MEK 1/2 and p-ERK1/2 in all types of ovarian follicles and corpora lutea in different phases of the estrous cycle of cattle. Bovine ovaries were harvested in a local slaughterhouse and the phase of the estrous cycle was determined, considering seven stages, defined as experimental groups: days 1-3 (n = 2), 4-6 (n = 5), 7-9 (n = 5), 10-12 (n = 3), 13-15 (n = 5), 16-18 (n = 5) and 19-21 (n = 5). After processing, the histological sections were subjected to immunohistochemistry using antibodies that specifically recognize the phosphorylated form of MEK 1/2 and ERK 1/2. Histological sections containing corpora lutea were also subjected to immunohistochemistry with antibodies that recognize p-BCL2 (B cell phospho lymphoma 2) and COX-2 (COX-2). The frequency of marked follicles was evaluated for the presence or absence of markup for the two cellular enzymes. The fragments of the corpus luteum were evaluated according to the scores of intensity for positive staining of the four antibodies. The frequencies of the markers studied in the follicles were compared using the chi-square. In preantral follicles, both MEK and ERK 1/2 showed high levels between 16 to 18 days. In the case of p-MEK, the greater activation of primordial follicles and primary held from 7 to 9. In secondary follicles, the less marked for p-MEK occurred in group 4 to 6. Levels of p-ERK began to rise from 13 to 15 days and subsequently decreased. Comparing the frequencies of MEK and ERK, there was statistic difference (p <0.0001) in antral follicles compared to other types of follicles. It was concluded that the intensity of activation of MAPKs MEK / ERK varies with the phases of the estrous cycle and follicular class studied. Since the corpora lutea were evaluated by analysis of variance after transforming the data, it was observed that the proteins studied showed variation in expression profile, in relation to the development, survival and death of the corpus luteum. Since COX-2, a precursor of prostaglandin, is capable of activating the pathways of MEK / ERK 1/2, it reduces the frequency of expression of cell survival factor BCL-2, leading to the corpus luteum at luteolysis. The in vivo evaluation of the activation profile of MAPKs without the use of hormonal protocols demonstrated the importance of this enzyme during the physiological reproductive process, raising new inquiries and providing opportunities to expand knowledge about the functioning of the hormone and its association with the cellular mechanisms activated by hormones