Chromium cytotoxicity in Steller sea lion lung, skin, and testes cells

Chromium cytotoxicity in Steller sea lion lung, skin, and testes cells

J.P. Wise Sr., C.E.C. Goertz, S.S. Wise, A.T. Morin, J.L. Dunn, F.M.D. Gulland, M. Bozza, S. Atkinson, and W.D. Thompson

Chromium cytotoxicity in Steller sea lion lung, skin, and testes cellsThis is part of Sea Lions of the World
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Description

The western population of Steller sea lions is endangered, and several hypotheses have been proposed to explain its decline. We are investigating the hypothesis that metals might be a factor in this decline. We found that chromium induced a concentration-dependent cytotoxicity in an organ-specific manner in Steller sea lion cells. Testicular cells were the most sensitive, and skin cells the most resistant. Lung cells were of intermediate sensitivity. Chromium uptake, measured by ICP-AES, increased with concentration in a cell-specific manner. When exposed to the same concentrations of sodium chromate, testicular cells accumulated greater intracellular concentrations of chromium ions than skin or lung cells did. This difference in chromium ion uptake may account for part of the differences in cytotoxicity among cell types. Tissue samples obtained opportunistically from pups were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Most pups had undetectable levels of chromium; however, in those where chromium was detected, its concentration was similar to that causing 50% cytotoxicity in culture. This finding suggests chromium may be a significant risk factor for Steller sea lions. These data were determined from a small number of samples from pre-weaned pups, and thus may not reflect adult exposure levels. However, given that chromium is known to accumulate and persist in human tissues, it is likely that adult exposures will prove to be much higher than pup levels. Further research is aimed at identifying chromium levels in
adult tissues, determining genotoxic levels and investigating effects of other metals on Steller sea lion cells.

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