MOLUSKUEN LISERI-GURUINEKO EPITELIOAREN ... - Euskara

Emaitzak eta eztabaida
Digestive cell turnover in the digestive gland epithelium of slugs
experimentally exposed to a mixture of cadmium and kerosene
Abstract: Slugs, Arion ater (L), have been proposed as sentinel organisms to assess soil environmental
health. In slugs under the influence of pollutants changes in the cell-type composition of the digestive-gland
have been observed, among these changes, the most remarkable one is the loss of digestive cells and the
related increase of excretory and calcium cells.The aim of the present work was to determine whether
digestive cell loss affects biomarkers of exposure and effect and whether is reversible in the digestive gland
of slugs exposed to a mixture or metal and organic pollutants under laboratory conditions. For these
purposes, slugs collected from a non-polluted site (Delika, Basque Country) were dosed with 10 µg Cd/gr
+ 30% of the water accommodated fraction of kerosene in the food for 27 days. Metal body burdens and
kerosene tissue levels were measured. The volume density of black silver deposits (Vv BSD ) revealed by
autometallography, and the activity of the enzyme acyl-CoA oxidase (AOX) were used as exposure
biomarkers. As effect biomarkes, changes in the volume density of the three cell types that constitute the
digestive gland epithelium in slugs (digestive, excretory and calcium cells) were calculated. Proliferating
cells were identified by means of bromodeoxyuridine (BrdU) immunohistochemistry. The results of the
present work revealed that the mixture of pollutants provoked an increase in Vv BSD and AOX activity as
well as a decrease in the number of digestive cells. Anyway, these changes had no effect in the capacity of
the digestive gland to accumulate or in the effect and exposure biomarkers employed. Moreover, the
change in cell-type composition measured in the digestive epithelium was reversible after 7 days of
detoxification. BrdU-labelling showed that exposure to pollutants provoked an enhanced digestive cell
proliferation, that perdured during detoxification
Key words: digestive gland, slugs, cell-type replacement, cadmium, kerosene, effect and exposure
biomarkers.
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