Avaliação do colágeno na cirrose hepática induzida por CCI4

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Transepithelial potential difference of the intestine and gallbladder of Hoplias malabaricus, a freshwater teleost. effect of urotensins I and II

This study analyzed the effect of the injection of urotensin I (UI) and urotensis II (UII) on the stabilization of the transepithelial potential difference (TPD) of the medium intestine, rectum, and gallbladder of Hoplias malabaricus to investigate if the transport of ions in these organs is affected "in vivo" by these neurohormones. The TPD of the medium intestine, rectum and gallbladder was serosa positive, and remained constant since the first measurement. The injection of both urotensins did not alter the stabilization of the TPD of the medium intestine and rectum when compared with saline-injected group. The injection of UI increased the TPD of the gallbladder in the beginning (0-10 min) of the stabilization period and in the interval of 20-30 min of the stabilization period when fishes were killed 2h and 4h after the injection, respectively, in relation to saline-injected group. The UII injection increased the TPD of the gallbladder only in the beginning (time 0) of the stabilization period in relation to saline when fishes were killed 2h after the injection. No changes in the TPD of the studied organs were detected when fishes were killed 4h after the injection of UII. This study confirms the hypothesis that UI and UII can participate in the regulation of the composition of the bile of fishes, since the injection of both hormones altered the TPD of the gallbladder of H. malabaricus.Este trabalho analisou o efeito da injeção da urotensina I (UI) e da urotensina 11 (UII) na estabilização da diferença de potencial transepitelial (DPT) do intestino médio, reto e vesícula biliar de Hoplias malabaricus, para verificar se o transporte de íons nestes órgãos é afetado "in vivo" por estes neuro-hormônios. A DPT do intestino médio, reto e vesícula biliar é serosa positiva, e seu valor permaneceu estável desde a primeira medida. A injeção de ambas urotensinas não modificou a estabilização da DPT do intestino médio e reto quando comparada com o grupo injetado com salina. A injeção de UI aumentou a DPT da vesícula biliar no início (0-10 min) do período de estabilização e no intervalo de 20-30 min do período de estabilização quando os peixes foram sacrificados 2 h e 4 h após a injeção, respectivamente, em relação ao grupo injetado com salina. A injeção de UII aumentou a DPT da vesícula biliar somente no início (tempo O) do período de estabilização em relação ao grupo tratado com salina sacrificado 2h após a injeção. Não houve alterações na DPT dos órgãos estudados quando os peixes foram sacrificados 4 h após a injeção da UII. Este estudo confirma a hipótese de que a UI e a UII poderiam participar na regulação da composição da bile dos peixes, uma vez que a injeção de ambos neuro-hormônios alterou a DPT da vesícula biliar de H. malabaricus

Effects of bromocriptine on serum prolactin levels, pituitary weight and immunoreactive prolactin cells in estradiol-treated ovariectomized rats : an experimental model of estrogendependent hyperprolactinemia

The present study was designed to assess the effects of bromocriptine, a dopamine agonist, on pituitary wet weight, number of immunoreactive prolactin cells and serum prolactin concentrations in estradioltreated rats. Ovariectomized Wistar rats were injected subcutaneously with sunflower oil vehicle or estradiol valerate (50 or 300 μg rat-1 week-1) for 2, 4 or 10 weeks. Bromocriptine (0.2 or 0.6 mg rat-1 day-1) was injected daily during the last 5 or 12 days of estrogen treatment. Data were compared with those obtained for intact control rats. Administration of both doses of estrogen increased serum prolactin levels. No difference in the number of prolactin cells in rats treated with 50 μg estradiol valerate was observed compared to intact adult animals. In contrast, rats treated with 300 μg estradiol valerate showed a significant increase in the number of prolactin cells (P<0.05). Therefore, the increase in serum prolactin levels observed in rats treated with 50 μg estradiol valerate, in the absence of morphological changes in the pituitary cells, suggests a “functional” estrogen-induced hyperprolactinemia. Bromocriptine decreased prolactin levels in all estrogen-treated rats. The administration of this drug to rats previously treated with 300 μg estradiol valerate also resulted in a significant decrease in pituitary weight and number of prolactin cells when compared to the group treated with estradiol alone. The general antiprolactinemic and antiproliferative pituitary effects of bromocriptine treatment reported here validate the experimental model of estrogen- induced hyperprolactinemic rats

Avaliação do estresse oxidativo e das defesas antioxidantes em fígado de animais cirróticos tratados com quercetina

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Hepatic oxidative stress in an animal model of sleep apnoea: effects of different duration of exposure

Background: Repeated apnoea events cause intermittent hypoxia (IH), which alters the function of various systems and produces free radicals and oxidative stress. Methods: We investigated hepatic oxidative stress in adult mice subjected to intermittent hypoxia, simulating sleep apnoea. Three groups were submitted to 21 days of IH (IH-21), 35 days of IH (IH-35), or 35 days of sham IH. We assessed the oxidative damage to lipids by TBARS and to DNA by comet assay; hepatic tissue inflammation was assessed in HE-stained slides. Antioxidants were gauged by catalase, superoxide dismutase, glutathione peroxidase activity and by total glutathione. Results: After IH-21, no significant change was observed in hepatic oxidative stress. After IH-35, significant oxidative stress, lipid peroxidation, DNA damage and reduction of endogenous antioxidants were detected. Conclusions: In an animal model of sleep apnoea, intermittent hypoxia causes liver damage due to oxidative stress after 35 days, but not after 21 days

Risks of dam construction for South American river dolphins : a case study of the Tapajós River

Funding: This study was funded by the Ministério da Ciência, Tecnologia e Inovação (MCTI) through Mamirauá Institute for Sustainable Development, with support from the Omacha Foundation (Colombia) and Whitley Fund for Nature.River dolphins are strongly affected by the construction of hydroelectric dams. Potential isolation in subpopulations above and below such dams and the resulting low genetic variability of these subpopulations can cause extinction at a local level. Here we aimed to estimate density and population size of South American river dolphins (boto Inia geoffrensis and tucuxi Sotalia fluviatilis), map their distribution, and estimate potential biological removal (PBR) limits in order to evaluate the effects of population fragmentation between planned dams in the Tapajós River, Amazonian basin, Brazil. Boat-based surveys were conducted following a line transect sampling protocol covering different dolphin habitats in 2 stretches of the river divided by rapids. The mark-recapture distance sampling method was applied to account for animals missed on the trackline. After the estimation of population sizes by habitat, PBR was calculated. The farthest upriver sighting of tucuxis was close to the São Luiz do Tapajós rapids, whereas the farthest upriver sighting of botos was upstream of the rapids, suggesting that botos move upstream through the rapids. Estimated abundance of tucuxis (3372 ind., CV = 0.38) was twice as high as that estimated for botos (1815 ind., CV = 0.4). The PBR ranged from 11 to 18 ind. for boto and 21 to 34 for tucuxi. Throughout this study, we identified low abundances of river dolphins compared to other Amazon rivers. Boto may not be sustainable at a population level, due primarily to population fragmentation which would result from the construction of the proposed dams. Precautionary measures are urgently needed before construction of dams begins in the Tapajós River.Publisher PDFPeer reviewe

THE EFFECT OF INTERMITTENT HYPOXIC TRAINING UNDER OXIDATIVE STRESS PARAMETERS IN WISTAR RATS FED ON STANDARD AND HIGH FAT DIET

Considerando-se que dietas ricas em gordura levam ao estresse oxidativo, causando lesões nas células e que o treinamento hipóxico intermitente (THI) aumenta as defesas antioxidantes endógenas em diversas situações, o objetivo deste estudo foi avaliar o efeito do THI em parâmetros de estresse oxidativo e defesas antioxidantes em fígado de ratos Wistar alimentados com dieta rica em gordura e/ou dieta padrão. Ratos Wistar foram divididos em grupos alimentados com dieta padrão ou rica em gordura. Os grupos foram submetidos a hipóxia intermitente (HI), 15 minutos HI (14-11% O2) intercalados com cinco minutos de re-oxigenação ou sessões de normóxia (N) (21% O2), por um período de duas horas diárias durante 30 dias. Os ratos Wistar alimentados com dieta padrão, e submetidas a HI, apresentaram uma redução de 37,7% na concentração de substâncias reativas ao ácido tiobarbitúrico (TBARS) e aumento de 34,66% e 39,8% no conteúdo de superóxido dismutase (SOD) e catalase (CAT), respectivamente, em comparação com o seu controlo (normoxia). No grupo com dieta rica em gordura, não houve diferença estatística entre os subgrupos HI e N. Nossos dados, que demonstram que o THI possui efeito antioxidante no fígado de ratos Wistar, argumentam em favor do uso alternativo de protocolos de hipoxia intermitente no tratamento de determinadas patologias