ABSTRACT
The Amazon rivers constitute the largest river basin in the world, with a high level of biodiversity. The Tocantins River is one of the most important rivers in this region, which has been impacted by different land uses. The objective of this study was to carry out a multi-evidence analysis focusing on the water quality of the Tocantins River, close to the municipality of Marabá-PA. We analyzed forest cover and water quality and, using the model organism Danio rerio, performed toxicity tests for histopathological effects, as well as the habitat selection approach by exposing fish to different river water samples in a multi-compartment device. The results showed that the studied area has already lost almost 30% of its forests in recent decades. Regarding water quality, the upstream (C1) and downstream (C5) points are the least impacted. On the other hand, the other points (C2-C4), closer to the city, greater input of pollutants was detected. Fish exposed to water samples from the most impacted sites showed several oedemas and hyperplastic cells in the gills. Regarding habitat selection behavior, there was a marked avoidance by samples with the highest contamination load. The results of this study lead to the understanding of the potential negative effects of human activities on local Amazonian biodiversity, since the potential toxicity of the environment, in conjunction with changes in the habitat selection process, could lead to a decline in populations of aquatic organisms, altering the environmental balance.
Subject(s)
Ecosystem , Environmental Monitoring , Rivers , Water Pollutants, Chemical , Water Quality , Zebrafish , Animals , Rivers/chemistry , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity , Biodiversity , Brazil , Forests , FishesABSTRACT
Esse estudo objetivou avaliar o efeito da ooforectomia sob os parâmetros histomorfométricos dos cardiomiócitos e quantificação de colágeno em ratas Wistar. Vinte ratas foram utilizadas e separadas em dois grupos: GI - ooforectomizada e GII - sham-ooforectomizada. Após a recuperação anestésica os animais foram acomodados em gaiolas e separados nas condições de ciclo claro/escuro 12/12h por um período de 6 meses. Passado o período experimental, os animais foram anestesiados, o coração retirado e mergulhado em formaldeído a 10%. Os fragmentos dos ventrículos foram submetidos ao processamento histológico e corados com hematoxilina e eosina. As análises histomorfométricas (área celular e área e volume nuclear) foram realizadas pelo microscópio de luz e software ImageJ versão 1.44. Os dados foram submetidos à análise ANOVA e quando significantes, complementados pelo teste t de student (p<0,001). Observou-se uma diminuição significativa das áreas celular e nuclear dos cardiomiócitos do grupo GI quando comparado ao grupo GII, bem como a área ocupada, pelo colágeno, no músculo cardíaco foi maior em GI, quando comparado a GII. Diante disso, conclui-se que as alterações observadas nos cardiomiócitos do grupo GI, sugerem uma maior atividade apoptótica nesse grupo, devido à diminuição dos níveis séricos do estrógeno provocado pela ooforectomia e o aumento da área ocupada pelo colágeno, no grupo ooforectomizado, está associada ao efeito cardioprotetor do estrógeno.
This study aimed to evaluate the effect of oophorectomy on the morphometric variables of cardiomyocytes and quantification collagen in Wistar rats. Twenty rats were used and divided into two groups: GI - ovariectomized and GII - sham-ovariectomized. After recovery from anesthesia the animals were housed in separate cages and under the conditions of light / dark cycle 12/12h for a period of six months. After the experimental period, the animals were anesthetized, the heart removed and immersed in 10% formaldehyde. The fragments of the ventricles were subjected to histological analysis and stained with hematoxylin and eosin. Histomorphometric analysis (cell area and nuclear area and volume) were performed by light microscopy and ImageJ software version 1.44. The data were submitted to ANOVA and when significant, complemented by Student's t test (p<0.001). There was a significant decrease in cellular and nuclear areas of the GI cardiomyocytes compared to GII and the area occupied by collagen was greater in cardiac muscle GI, when compared to GII. Therefore, it is concluded that the changes observed in the GI group cardiomyocytes, suggest a higher apoptotic activity in this group, due to decreased serum estrogen levels caused by ovariectomy and increased area occupied by collagen in oophorectomized group is associated the cardioprotective effect of estrogen.