Liver alterations in two freshwater fish species (Carassius auratus and Danio rerio) following exposure to different TiO₂ nanoparticle concentrations.
The toxicity of titanium dioxide nanoparticles (TIO₂ NPs) and oxidative stress effects were studied in two freshwater fish species (Carassius auratus and Danio rerio) exposed for 21 days to different concentrations (0.01, 0.1, 1, 10, 100/mgL) of TiO₂ NPs and to a control (tap water). Additional fish were transferred to clean water for 14 days to assess the ability to recover from exposure to TiO₂ NPs. Activities of the enzyme glutathione-S-transferase (GST) and lipid peroxidation (LPO) (malondialdheyde) were measured as indicators of oxidative stress. Histological and ultra-structural changes in livers from both species of fish were evaluated by light and electron microscopy. Results show a general GST activity increase according to TiO₂ NPs concentrations, which is in agreement with data from LPO. After 21 days, GST activities decreased possibly caused by suppression of GST synthesis as a result of severe stress. Histological and ultra-structural analysis of livers from exposed fish show degeneration of the hepatic tissue and alterations in hepatocytes such as glycogen depletion and an increase in lipofucsin lysosome-like granules. After a depuration period a partial recovery for biochemical markers and cells was observed. The results suggest that TiO₂ promotes alterations in hepatic tissues compatible with oxidative stress.
REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Centro de Química Fina e Biotecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Mário S
MS
Diniz
António P Alves
AP
de Matos
Joana
J
Lourenço
Luísa
L
Castro
Isabel
I
Peres
Elsa
E
Mendonça
Ana
A
Picado
D000818:Animals; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity; D005982:Glutathione Transferase / Q000378:metabolism; D006054:Goldfish / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects / Q000648:ultrastructure; D006651:Histocytochemistry; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D008854:Microscopy, Electron; D053758:Nanoparticles / Q000378:metabolism / Q000633:toxicity*; D009195:Peroxidase / Q000378:metabolism; D014025:Titanium / Q000378:metabolism / Q000633:toxicity*; D015027:Zebrafish / Q000378:metabolism*
D004785:Environmental Pollutants; C009495:titanium dioxide; D014025:Titanium; D009195:Peroxidase; D005982:Glutathione Transferase