Detalhes bibliográficos
| Ano de defesa: |
2019 |
| Autor(a) principal: |
Sanchez, Camila do Carmo
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| Orientador(a): |
Buzalaf, Camila Peres
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| Banca de defesa: |
Não Informado pela instituição |
| Tipo de documento: |
Dissertação
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| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade do Sagrado Coração
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| Programa de Pós-Graduação: |
Ciência e Tecnologia Ambiental
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| Departamento: |
Ciências Exatas e Sociais Aplicadas
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| País: |
Brasil
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| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
https://tede2.usc.br:8443/handle/tede/465
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Resumo: |
Pharmaceuticals are considered to be emerging pollutants with negative effects on terrestrial and aquatic environments. Glucocorticoids (GCs) are a group of steroid hormones that play an important role as physiological regulators. Dexamethasone is widely used, due to its anti-inflammatory properties, whose release into the aquatic environment is relevant. In addition, there are no studies in the literature dealing with the toxic effects of DEX, as well as the products derived from its degradation, in mammals. Thus, the objective of this work was to promote the photocatalytic degradation of DEX and to evaluate the cytotoxicity of the derivatives in hepatocytes and macrophages. UV-C, TiO2, TiO2 + UV-C light and UV-A light conditions were tested by UV-vis spectrophotometer (242 nm). The photocatalytic activity in the total period of 1h, being evaluated the samples every 10 min there was alteration of the spectral profile in both conditions (UV-C light and UV-C + TiO2 light) after 10 minutes, compared to DEX in the previous initial period photodegradation. In the subsequent periods, no changes were observed in relation to the 30 min period. No differences were observed in the presence or absence of TiO2. Degradation was confirmed by analysis of the samples at different HPLC experimental periods and conditions. Exposure of DEX to UV-C light promoted the appearance of its derivatives, revealed by the chromatographic peaks at times of retention smaller than that of DEX. Cytotoxicity was evaluated in hepatocytes and macrophages only for DEX at different concentrations (0,1, 1, 10, 100 and 1000 μM) at times of 24 and 72 hours. In 24h, DEX alone at the concentration of 1000 μM significantly reduced the viability of HepG2 hepatocytes (P <0,05). At concentrations of 1, 10, 100 and 1000 μM inhibited significantly (P <0,05). THP-1 cells were induced to cell differentiation in macrophages. The effect of DEX, in different concentrations, in the period of 24 h, showing no significant change in cell viability at all concentrations tested. In the 72 h period, the number of viable cells was significantly inhibited in relation to the control (P <0,05). The samples obtained under the conditions, UV-C light and UV-C + TiO2 light at 0, 0,5 and 1 hour times were also analyzed by MTT in the 72 h period. The concentrations of 10 and 100 μM DEX for comparative purposes, since the degradation was performed from 100 μM DEX. Samples obtained in UV-C light conditions (containing undegraded DEX 100 μM), 0,5 h and 1 h (containing DEX byproducts at unknown concentrations) reduced the viability of hepatocytes compared to control. In addition, samples of the UV-C + TiO2 light condition, at periods of 0,5 and 1 h, significantly reduced cell viability. Although this reduction is apparently lower than that induced in the light samples alone, there was no significant difference between the conditions. The results allowed to conclude that the by-products of DEX obtained from photocatalysis interfere in the metabolism of human cells and are relevant for the ecotoxicological studies. |
