A model for acute iron overload in sea bass (Dicentrarchus labrax L.)

Evaluation of several parameters involved in iron metabolism was carried out after intraperitoneal (i.p.) injection with iron dextran (IDx) in sea bass (Dicentrarchus labrax L.). After treatment, a rapid mobilization of IDx from the peritoneal cavity to other organs was observed. This was followed by a modification of normal peripheral blood iron parameters. Total iron (TI) and transferrin saturation (TS) rose rapidly, to 4.14 microg/ml and 83.7%, respectively, on day 3. In contrast, unsaturated iron binding capacity (UIBC) dropped from 3.19 microg/ml (at day 0) to 0.90 microg/ml on day 3. Tissue iron content was determined by atomic absorption spectometry (AAS). Three days post-IDx injection, values of iron concentration in liver, spleen and head kidney were significantly higher than control values (15, 6 and 9-fold increase, respectively). Samples of liver, spleen and head kidney were processed for routine histology, and the Perl's method was used for iron staining. Histological sections of the IDx-treated animals showed iron deposition in all tissues studied. In the liver, the iron was evenly distributed over the whole organ, being present in the hepatocytes. In the head kidney and spleen, the iron deposition was mainly observed in the melanomacrophage centres (MMCs). The present study characterizes several parameters involved in iron metabolism, and develops a fish model, of iron overload, which can be used in further studies of iron toxicity and iron-induced susceptibility to bacterial infections.