Manganese effects on haematopoietic cells and circulating coelomocytes of Asterias rubens (Linnaeus).
Manganese (Mn) is a naturally abundant metal in marine sediments where it mainly occurs as MnO(2). During hypoxic conditions it is converted into a bioavailable state, Mn(2+), and can reach levels that previously have shown effects on immune competent cells of the crustacean, Nephrops norvegicus. Here we investigated if Mn also affects circulating coelomocytes and their renewal in the common sea star, Asterias rubens, when exposed to concentrations of Mn that can be found in nature. When the sea stars were exposed to Mn it accumulated in the coelomic fluid and the number of circulating coelomocytes, in contrast to what was recorded in Nephrops, increased significantly. By using the substitute nucleotide, 5-bromo-2'-deoxyuridine, BrdU, for tracing cell division and by recording mitotic index by nuclei staining, we found that Mn induced proliferation of cells from a putative haematopoietic tissue, the coelomic epithelium. In addition, the haematopoietic tissue and coelomocytes showed stress response in terms of changes in HSP70 levels and protein carbonyls, as judged by immunohistochemistry and Western blotting. Measurement of dehydrogenase activity, using MTS/PMS, revealed that Mn showed cytotoxic properties. We also found that the phagocytotic capacity of coelomocytes was significantly inhibited by Mn. It was concluded that the exposure of A. rubens to Mn induced renewal of coelomocytes and impaired their immune response.
Oweson
Carolina
C
Department of Marine Ecology, Göteborg University, Kristineberg 566, 45034 Fiskebäckskil, Sweden.
Sköld
Helen
H
Pinsino
Annalisa
A
Matranga
Valeria
V
Hernroth
Bodil
B
D000818:Animals; D047271:Asterias / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015153:Blotting, Western; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006434:Hemocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008345:Manganese / Q000633:toxicity*; D008940:Mitotic Index; D010587:Phagocytosis / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D018840:HSP70 Heat-Shock Proteins; D014874:Water Pollutants, Chemical; D008345:Manganese