Investigação do potencial carcinogênico da exposição atmosférica ao pó de cromo trivalente em Rattus norvegicus

• Ano de defesa: 2021
• Autor(a) principal: Teixeira, Justijânio Cácio Leal
• Orientador(a): Monteiro, Helena Serra Azul
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Cromo; Neoplasias; Riscos Ocupacionais
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/59746

Chromium is a heavy metal and a well known environmental contaminant. Chromium (III) was initially considered a relatively non-toxic agent. On the other hand, evidence suggests that this metal may contribute to mutations in genetic material and induction of genetic instability, which in turn are determining factors for carcinogenesis processes. Thus, the present study aimed to evaluate the potential for induction of genomic instability and carcinogenesis from atmospheric exposure to chromium (III) dust in Rattus norvegicus. To this end, 40 animals were divided into two exposure groups: the exposed group (n = 20 males) were exposed for 4 h to atmospheric chromium (III) dust at a concentration of 500 µg/m3 daily for a total period of 14 weeks; The control group consisted of 20 animals (males) exposed to filtered air (HEPA) for an equal period of exposure. During the exposure period, the animals were evaluated for general toxicological, behavioral and locomotor parameters, as well as for the development of perceived or palpable lesions. In addition, analyzes of the antioxidant profile (catalase, superoxide dismutase and glutathione) were performed at the end of each week of exposure. Finally, blood samples were collected for biochemical and hematological processing, as well as lung, liver and kidney fragments were collected for histopathological analysis. In addition, bone marrow samples were collected for genotoxic evaluation, mutagenic profile and cell death analysis. Chromium (III) 500 µg/m3 produced no behavioral changes in exposed animals. On the other hand, chromium produced hitopathological changes in the liver, kidneys and lung. Also, it induced an increase (p<0.05) of malondialdehyde and nitrite, accompanied by an increase (p<0.05) of catalase and superoxide dismutase levels. Conversely, there was a prominent reduction in glutathione peroxidase and serum reductase levels in exposed animals. In this study, the metal also induced biochemical changes in liver and renal function markers, but without hematological changes. Also, chromium (III) produced an increase (p<0.05) in the index and frequency of DNA damage to animal bone marrow cells, as well as causing (p<0.05) mutagenicity and an increase (p<0.05) in apoptosis and necrosis frequency. This study demonstrated the oxidative, genotoxic, mutagenic and cytotoxic effects of atmospheric exposure to chromium (III) dust. These data will provide information on the genetic instability and carcinogenicity related to chromium compounds, which are relevant for the formulation of occupational carcinogenesis risk prevention strategies.