Sublethal effects of repeated intraperitoneal cadmium injections on rainbow trout (Oncorhynchus mykiss).

Acute and chronic effects of cadmium have been widely described for different aquatic organisms and exposure routes. However, there is clearly a lack of information on the potential of cadmium to cause genotoxic effects. This work presents genotoxic and nongenotoxic parameters analyzed in cadmium-exposed rainbow trout. The assessment was performed for sublethal levels after long-term exposure using six intraperitoneal injections of 0.5 mg/kg (Day 1), 1 mg/kg (Days 3, 7 and 11), and 2 mg/kg (Days 15 and 19) to allow precise estimation of the dose. Cadmium accumulation in target tissues, essential metal mobilization by cadmium at the subcellular and tissue levels, and induction of metallothioneins were selected as exposure and effect parameters. Induction of micronuclei and variation in DNA content (expressed as variation coefficient in the G1 phase of the cell cycle) in blood cells, determined by flow cytometry, were selected as biomarkers for genotoxic effects. Cadmium accumulation, induction of metallothioneins, and mobilization of essential metals at the subcellular level were observed in different organs in response to cadmium exposure. The highest metallothionein induction was observed in liver, reaching 270+/-90 nmol/g wet tissue in treated fish versus 2.68+/-1.1 nmol/g wet tissue in controls. The highest cadmium accumulation was also observed in the liver (27.8+/-9.5 microgram Cd/g wet wt in treated animals versus 1.0+/-1.7 in the control group). However, no genotoxic effects were observed in blood cells. The frequency of micronuclei was 0.012+/-0.008 for the control group and 0.013+/-0.021 for treated animals. The variation coefficient of G1-phase nuclei was 3.61+/-0.66 and 3.22+/-0.29 for control and cadmium-exposed groups, respectively. Thus, it is concluded that under the experimental conditions employed here, treatment of rainbow trout with cadmium chloride at doses that produce significant toxicological alterations at the tissue and subcellular levels does not provoke observable alterations in the genotoxic parameters considered in this study.

[1]  S. Paglialunga,et al.  Induction of micronuclei in Vicia faba root tips treated with heavy metals (cadmium and chromium) in the presence of NTA. , 1988, Mutation research.

[2]  J. Tarazona,et al.  A proposed method to diagnose acute copper poisoning in cultured rainbow trout, (Oncorhynchus mykiss) , 1993 .

[3]  N. Keiding,et al.  Long-term storage of samples for flow cytometric DNA analysis. , 1983, Cytometry.

[4]  John R. Jones,et al.  Evaluation of Metallothionein Measurement as a Biological Indicator of Stress from Cadmium in Brook Trout , 1987 .

[5]  Y. Mizuguchi,et al.  Action of some metal ions on yeast chromosomes. , 1982, Chemical & pharmaceutical bulletin.

[6]  H. Petering.  Some observations on the interaction of zinc, copper, and iron metabolism in lead and cadmium toxicity. , 1978, Environmental health perspectives.

[7]  M. Nüsse,et al.  Chapter 9 Measurement of Micronuclei by Flow Cytometry , 1994 .

[8]  J. G. O'neill.  Effects of intraperitoneal lead and cadmium on the humoral immune response ofSalmo trutta , 1981, Bulletin of environmental contamination and toxicology.

[9]  T. Gill,et al.  Effects of cadmium on plasma catecholamines in the american eel anguilla rostrata , 1992 .

[10]  P. Worsfold,et al.  Pollution Threat of Heavy Metals in Aquatic Environments , 1988 .

[11]  L. Förlin,et al.  Cadmium‐induced changes in gill morphology of zebrafish, Brachydanio rerio (Hamilton–Buchanan), and rainbow trout, Salmo gairdneri Richardson , 1985 .

[12]  A. Heath.  Water Pollution and Fish Physiology , 1987 .

[13]  R. Schiestl,et al.  Carcinogens induce intrachromosomal recombination in yeast. , 1989, Carcinogenesis.

[14]  George W. Ware.  EEC Water Quality Objectives for Chemicals Dangerous to Aquatic Environments (List 1) , 1994 .

[15]  J. Boyle,et al.  Effect of cadmium ingestion on cadmium and zinc profile in male and female rat liver cytosol. , 1978, Biochemical pharmacology.

[16]  K. Gopal,et al.  Immune responses to Aeromonas hydrophila in cat fish (Heteropneustis fossilis) exposed to cadmium and hexachlorocyclohexane , 1992, Bulletin of environmental contamination and toxicology.

[17]  E. Zeiger,et al.  Conditions for detecting the mutagenicity of divalent metals in Salmonella typhimurium , 1992, Environmental and molecular mutagenesis.

[18]  S. De Flora,et al.  Mutagenicity testing with TA97 and TA102 of 30 DNA-damaging compounds, negative with other Salmonella strains. , 1984, Mutation research.

[19]  J. Solbé,et al.  Cadmium accumulation and protein binding patterns in tissues of the rainbow trout, Salmo gairdneri. , 1986, Environmental health perspectives.

[20]  A. Glynn,et al.  Xanthate effects on cadmium intracellular distribution in rainbow trout (Oncorhynchus mykiss) gills , 1991 .

[21]  M. Cherian,et al.  Comparison of metallothionein determination by polarographic and cadmium-saturation methods. , 1982, Toxicology and applied pharmacology.

[22]  D. Svendsgaard,et al.  Evaluation of 10 chemicals for aneuploidy induction in the hexaploid wheat assay. , 1991, Mutagenesis.