RESUMO

To assess the effect of nesiritide on the endothelial function of iliac arteries following endothelia trauma. Right iliac artery trauma was created with a balloon catheter. Ten rabbits were treated with a 4-week subcutaneous injection of nesiritide at a fixed daily dose of 0.1mg/kg. Ten rabbits received daily normal saline injection. Plasma endothelin 1 (ET-1), nitric oxide (NO), and Von Willebrand Factor (vWF) were measured before and after the therapies. Tissue proliferating cell nuclear antigen (PCNA) was measured after the treatment. After the treatment, in the therapeutic group, the area under internal elastic membrane and the residual lumen area were higher than in the normal saline group (P <0.05). The plasma levels of ET-1 (91.6±6.8 vs 114.9±6.3 ng/L, P =0.001), vWF (134.6±10.8% vs 188.8±10.4%, P =0.001) and the ratio of PCNA positive expression (11.7±4.2% vs 36.2±11.4%, P =0.005) in the therapeutic group was lower than in the normal saline group, while the plasma levels of NO was higher (89.7±9.3 vs 43.5±5.3 µmol/L, P =0.001). Nesiritide inhibited remodeling of rabbit iliac artery following endothelial trauma. The inhibition of vascular remodeling may be related to the alleviated endothelial dysfunction and reduced expression of tissue proliferating cell nuclear antigen

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RESUMO

The corpus luteum (CL) undergoes drastic changes in its function and structure during the estrous cycle. To secrete a sufficient amount of progesterone (P4) to ensure the occurrence of pregnancy in a cow with a body weight greater than 500 kg, the bovine CL weighs 5-8 g which is 2-3 thousand times heavier than rat CL. If pregnancy does not occur successfully, rapid luteolysis is caused by prostaglandin F2α (PGF2α) that is released from the endometrium around days 17-19 of the estrous cycle in the cow. Thus, it is clear that the bovine CL lifespan is controlled by well-coordinated mechanisms. As the CL matures, the steroidogenic cells establish contact with many capillary vessels, so that the CL is composed of a large number of vascular endothelial cells that can account for up to 50% of all cells in the bovine CL. Also, luteal endothelial cells secrete several vasoactive substances such as PGF2α, nitric oxide, endothelin-1 and angiotensin II that regulate blood flow as well as P4 secretion in an autocrine/paracrine manner within the CL. Therefore, blood vessels and endothelial cells within the CL have an essential role in luteal function in the cow, suggesting that the study of vasoactive molecules from the CL is of great importance to give an insight into systems which regulate luteolysis locally. In the present review, we describe novel concepts on the luteolytic mechanisms in the cow, with emphasis on luteal blood flow and vasoactive molecules.

Assuntos

RESUMO

The corpus luteum (CL) undergoes drastic changes in its function and structure during the estrous cycle. To secrete a sufficient amount of progesterone (P4) to ensure the occurrence of pregnancy in a cow with a body weight greater than 500 kg, the bovine CL weighs 5-8 g which is 2-3 thousand times heavier than rat CL. If pregnancy does not occur successfully, rapid luteolysis is caused by prostaglandin F2α (PGF2α) that is released from the endometrium around days 17-19 of the estrous cycle in the cow. Thus, it is clear that the bovine CL lifespan is controlled by well-coordinated mechanisms. As the CL matures, the steroidogenic cells establish contact with many capillary vessels, so that the CL is composed of a large number of vascular endothelial cells that can account for up to 50% of all cells in the bovine CL. Also, luteal endothelial cells secrete several vasoactive substances such as PGF2α, nitric oxide, endothelin-1 and angiotensin II that regulate blood flow as well as P4 secretion in an autocrine/paracrine manner within the CL. Therefore, blood vessels and endothelial cells within the CL have an essential role in luteal function in the cow, suggesting that the study of vasoactive molecules from the CL is of great importance to give an insight into systems which regulate luteolysis locally. In the present review, we describe novel concepts on the luteolytic mechanisms in the cow, with emphasis on luteal blood flow and vasoactive molecules.(AU)

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RESUMO

Além do controle neuroendócrino do eixo hipotalâmico-hipofisáriogonadal existem fatores autócrinos e parácrinos que controlam o crescimento, seleção e ovulação nos mamíferos. Estes fatores ainda não estão bem estabelecidos. Objetivando analisar as variações nas concentrações plasmáticas da endotelina-1 em um ciclo estral bovino e seus efeitos sobre o cultivo de células da granulosa, foram analisadas amostras plasmáticas de 5 dias (0, 1, 3, 7 e 13) de um ciclo estral, tendo como base o dia da ovulação (dia 0) e 3 horas (8, 13 e 16) do 14º dia do ciclo. As variações nas concentrações plasmáticas de endotelina-1 não foram significativas para os dias assim como para as horas do dia analisado. Células da granulosa obtidas de folículos antrais foram cultivadas durante 48 horas com diferentes concentrações de endotelina. Os resultados demonstraram que a endotelina atua de maneira dosedependente estimulando a produção de progesterona e inibindo o crescimento celular.(AU)

Besides the neuroendocrine control of the hypotalamic-hypophisarygonodal axis there are autocrines and paracrines factors that control the growth, selection and ovulation in the mammals. These factors are not well established yet. Aiming to analyze the variations in the endotelin-1plasmatic concentrations in a bovine estral cycle and their effects on the culture of granulosa cells, plasma samples of 5 days (0,1,3,7 and 13) from an estral cycle have been analyzed, having as basis the ovulation day (day 0) and 3 hours (8,13,16) of the fourteenth day of the cycle. The variations in the endothelin-1 concentrations were not significant for the days as well as for the hours of the analyzed day. Granulosa cells obtained from antral follicles were cultivated during 24 hours with different concentrations of endothelin. The results demonstrated that the endothelin-1 acts in a dose-dependent manner stimulating the production of progesterone and inhibiting the cellular growth.(AU)

Assuntos

RESUMO

Além do controle neuroendócrino do eixo hipotalâmico-hipofisáriogonadal existem fatores autócrinos e parácrinos que controlam o crescimento, seleção e ovulação nos mamíferos. Estes fatores ainda não estão bem estabelecidos. Objetivando analisar as variações nas concentrações plasmáticas da endotelina-1 em um ciclo estral bovino e seus efeitos sobre o cultivo de células da granulosa, foram analisadas amostras plasmáticas de 5 dias (0, 1, 3, 7 e 13) de um ciclo estral, tendo como base o dia da ovulação (dia 0) e 3 horas (8, 13 e 16) do 14º dia do ciclo. As variações nas concentrações plasmáticas de endotelina-1 não foram significativas para os dias assim como para as horas do dia analisado. Células da granulosa obtidas de folículos antrais foram cultivadas durante 48 horas com diferentes concentrações de endotelina. Os resultados demonstraram que a endotelina atua de maneira dosedependente estimulando a produção de progesterona e inibindo o crescimento celular.

Besides the neuroendocrine control of the hypotalamic-hypophisarygonodal axis there are autocrines and paracrines factors that control the growth, selection and ovulation in the mammals. These factors are not well established yet. Aiming to analyze the variations in the endotelin-1plasmatic concentrations in a bovine estral cycle and their effects on the culture of granulosa cells, plasma samples of 5 days (0,1,3,7 and 13) from an estral cycle have been analyzed, having as basis the ovulation day (day 0) and 3 hours (8,13,16) of the fourteenth day of the cycle. The variations in the endothelin-1 concentrations were not significant for the days as well as for the hours of the analyzed day. Granulosa cells obtained from antral follicles were cultivated during 24 hours with different concentrations of endothelin. The results demonstrated that the endothelin-1 acts in a dose-dependent manner stimulating the production of progesterone and inhibiting the cellular growth.

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RESUMO

As endotelinas säo peptídeos de 21 aminoácidos produzidas em vários tipos de tecidos, reconhecidas como vasoconstritores endógenos potentes. Há quatro tipos de endotelinas: ET-1, 2, 3 e 4). A Endotelina 1 (ET-1) é o único membro da familia produzida tanto nas células endoteliais como nas células musculares lisas dos vasos. A ET-1 causa vasoconstriçäo de quase todas artérias e veias, além de produzir proliferaçÝo das células musculares lisas dos vasos e modular a produçäo hormonal. A produçäo da endotelina é regulada por vários estímulos mecânicos e químicos como hipóxia, lesäo da parede vascular, trombina, angiotensina II e insulina. Os antagonistas de seus receptores sugerem que esses peptídeos desempenham importantes papéis no desenvolvimento de várias patologias tais como a hipertensäo sistêmica, aterosclerose e insuficiência cardiaca congestiva

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