Micronucleus cytome assay in the differential assessment of cytotoxicity and genotoxicity of cadmium and lead in Amietophrynus regularis

Authors

  • C.G. Alimba Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Nigeria
  • A.M. Aladeyelu Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Nigeria
  • I.A. Nwabisi Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Nigeria
  • A.A. Bakare Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Nigeria

DOI:

https://doi.org/10.17179/excli2017-887

Keywords:

acute toxicity, amphibian decline, cadmium and lead compounds, cytotoxicity, genome instability, micronucleus cytome assay, toad

Abstract

Amphibians are increasingly being used as bio-indicator of contamination in ecosystems due to their sensitivity to xenobiotics in the environment. Cadmium and lead compounds, ubiquitous mutagens and carcinogens, are capable of eliciting genome instability in adult toads which may enhance amphibian decline. Micronucleus cytome (MN-cyt) assay, a comprehensive cytogenetic test for the assessment of genome instability induced by xenobiotics in organisms, was utilized in the differential cytogenotoxic evaluation of Cd and Pb in adult Amietophrynus regularis. A. regularis was exposed to six concentrations (8 - 512 mg/L) of the metal solutions to determine 96 h acute toxicity. Four toads per group were exposed to five sub-lethal concentrations (5 - 75 %) of the 96 h LC50 of the metals for 14 days. At post exposure, bone marrow and peripheral erythrocytes were collected for MN-cyt analysis. The metals induced differential concentration and time-dependent increase in mortality with 96 h LC50 of 36.36 mg/L (Cd) and 112.06 mg/L (Pb). No observable effective concentrations (NOEC); Cd=8 and Pb=32 (mg/L) and Lowest observable effective concentrations (LOEC); Cd=16 and Pb=64 (mg/L) were recorded for the metals. Derived toxicity factor (TF) showed that Cd was 3.08 times more toxic to the toads than Pb. The metal solutions induced significant (p<0.05) increase in frequencies of MN, binucleated, nuclear bud, notch, lobe, vacuolated erythrocytes, apoptosis and necrosis compared to the negative control. Cd elicited 1.42 and 3.26 folds increase in MN and NAs respectively, than Pb. MN-cyt assay is a suitable cytogenetic tool for assessing genome instability in A. regularis. Increased genetic instability induced by Cd and Pb may be associated with genetic related syndromes; neoplasms, reproductive dysfunctions and mortality. This suggests threat to amphibian health and may enhance population decline.

Downloads

Published

2018-01-11

How to Cite

Alimba, C., Aladeyelu, A., Nwabisi, I., & Bakare, A. (2018). Micronucleus cytome assay in the differential assessment of cytotoxicity and genotoxicity of cadmium and lead in Amietophrynus regularis. EXCLI Journal, 17, 89–101. https://doi.org/10.17179/excli2017-887

Issue

Vol. 17 (2018)

Section

Original articles

License

Authors who publish in this journal agree to the following terms:

  • The authors keep the copyright and grant the journal the right of first publication under the terms of the Creative Commons Attribution license, CC BY 4.0. This licencse permits unrestricted use, distribution and reproduction in any medium, provided that the original work is properly cited.
  • The use of general descriptive names, trade names, trademarks, and so forth in this publication, even if not specifically identified, does not imply that these names are not protected by the relevant laws and regulations.
  • Because the advice and information in this journal are believed to be true and accurate at the time of publication, neither the authors, the editors, nor the publisher accept any legal responsibility for any errors or omissions presented in the publication. The publisher makes no guarantee, express or implied, with respect to the material contained herein.
  • The authors can enter into additional contracts for the non-exclusive distribution of the journal's published version by citing the initial publication in this journal (e.g. publishing in an institutional repository or in a book).