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Planarian neoblast micronucleus assay for evaluating genotoxicity
Tanise Knakievicz1, Priscila Alves da Silveira, Henrique Bunselmeyer Ferreira
1Laboratório de Biologia Molecular de Cestódeos, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500-Prédio 43-421, sala 210, Caxia Postal 15005, Porto Alegre, RS, Brazil
A new genotoxicity assay using planarian stem cells (neoblasts) effectively detects DNA damage in regenerating worms exposed to genotoxic agents like gamma-rays, MMS, and CP. This assay offers a promising tool for monitoring environmental pollutants.
Area of Science:
- * In vivo genotoxicity testing
- * Aquatic toxicology
- * Stem cell biology
Background:
- * Planarian neoblasts are highly proliferative somatic stem cells, sensitive to genotoxic agents.
- * Existing genotoxicity assays may have limitations in detecting damage in aquatic organisms.
- * Developing novel assays is crucial for environmental monitoring.
Purpose of the Study:
- * To develop and validate a neoblast-based micronucleus (MN) assay for genotoxicity assessment in freshwater planarians.
- * To evaluate the assay's sensitivity to known clastogenic agents (gamma-rays, MMS, CP).
- * To assess the potential of this assay for monitoring environmental genotoxicity.
Main Methods:
- * Two planarian species, Girardia tigrina and Girardia schubarti, were used.
- * Neoblast micronucleus (MN) frequency was measured in intact and regenerating planarians exposed to gamma-rays, methyl methanesulphonate (MMS), and cyclophosphamide (CP).
- * Regeneration was induced by decapitation to stimulate neoblast proliferation.
Main Results:
- * Genotoxic agents induced a significant increase in MN frequency in regenerating planarian neoblasts, but not in intact neoblasts.
- * The assay detected low doses of gamma-rays (0.5 Gy), MMS (0.8 µM), and CP (100 mM).
- * MN frequencies returned to baseline levels after regeneration, confirming the assay reflects acute damage.
Conclusions:
- * The planarian neoblast MN assay is a sensitive method for detecting chromosomal damage induced by genotoxic agents in regenerating planarians.
- * This assay provides a valuable tool for assessing the genotoxic impact of environmental pollutants on freshwater organisms.
- * Further standardization could establish this assay as a key alternative in ecotoxicological monitoring.
