Chromosomal aberrations in vitro induced by aneugens

Area of Science:

• Cytogenetics
• Molecular Toxicology
• Cell Biology

Background:

• Aneugens are known to disrupt cell division and possess aneugenic potential.
• A potential link between aneugen-induced cell division disturbance and clastogenic effects requires investigation.

Purpose of the Study:

• To determine if a relationship exists between cell division disturbance and clastogenic potential of aneugens.
• To investigate the induction of structural chromosomal aberrations, polyploid cells, and mitotic index alterations by colcemid, colchicine, and vincristine in CHO cells.

Main Methods:

• Chinese Hamster Ovary (CHO) cells were treated with varying concentrations of colcemid, colchicine, and vincristine.
• Analysis included assessment of structural chromosomal aberrations, polyploidy, and mitotic index.
• Dose-response effects and clastogenic potential in both diploid and tetraploid cells were evaluated.

Main Results:

• Low to intermediate concentrations of aneugens increased polyploidy and mitotic index but did not induce structural aberrations.
• High concentrations of colcemid and colchicine induced structural aberrations in diploid cells; colchicine and vincristine were clastogenic in tetraploid cells.
• A threshold effect was observed for clastogenicity, and tetraploidy itself was associated with increased aberrations, independent of aneugen treatment.

Conclusions:

• No direct relationship was found between aneugen-induced cell cycle disturbance and the incidence of structural chromosomal aberrations for the tested compounds.
• The clastogenic effects of aneugens are concentration-dependent and can occur in polyploid cells.
• Tetraploid cells exhibit a higher baseline frequency of structural chromosomal aberrations.