Evaluation of Clastogenic/Aneugenic Damage Using the FISH Micronucleus Assay in Mice Exposed to Chromium (VI)

Abstract

Background/Aim: Exposure to chromium (VI) [Cr (VI)] has been postulated to be associated with the induction of cancer. In vivo studies utilizing biomarkers of genotoxic damage could aid in elucidating the mechanisms underlying the genotoxic effects of Cr(VI) and their relationship with carcinogenesis. In this study, the origin (clastogenic and/or aneugenic damage) and kinetics of micronuclei (MN) induced by Cr(VI) were investigated. Materials and Methods: Hsd:ICR female mice were divided into groups of five individuals each. MN kinetics were measured in groups treated with 20 or 25 mg/kg CrO 3 intraperitoneally using acridine orange-coated slides in peripheral blood obtained from the caudal vein 0, 12, 24, 36, 48, 60, and 72 h after treatment. Whereas identification of MN with centromeric DNA (MNK+) was measured at the dose of 20 mg/kg of CrO 3 , using fluorescence in situ hybridization (FISH) with a centromere-specific probe in peripheral blood obtained at 0, 12, and 48 h after treatment. Control groups were administered vehicle only. Results: Total MN were quantified and the clastogenic/aneugenic effects of Cr(VI) were evaluated based on the proportion of MNK+ versus micronuclei without centromeric DNA (MNK-). There was a significant increase in MN frequencies beginning at 12 h in the Cr(VI)-treated groups demonstrating its genotoxicity. When calculating the MNK+ as a percentage of the total MN, the increase was significant beginning 12 h after treatment. Conclusion: The fact that the MNK+ and MNK-were observed at both evaluation times corroborates Cr(VI) as a genotoxic agent and demonstrates that both clastogenic and aneugenic damages are involved in the formation of MN.

A comparative study on chromium‐induced micronuclei assessment in the peripheral blood of Hsd:ICR mice

“…route was selected to compare the direct genotoxic effects of Cr(III) and Cr(VI). Our observations are in agreement with previous reports, indicating a significant elevation in MN formation in both male and female subjects (De Flora et al, 2006;García-Rodríguez, Santiago-Moreno, et al, 2023;Itoh & Shimada, 1996;Li et al, 2004;Sawicka et al, 2021). Males exhibited a more pronounced genotoxic effect compared to females, after administration of Cr compounds, except for Na 2 Cr 2 O 7 , which produced similar responses in both genders.…”

“…The Cr(III) compounds selected were CrK(SO 4 ) 2 and CrCl 3 , while Cr(VI) compounds included CrO 3 , K 2 CrO 4 , K 2 Cr 2 O 7 , and Na 2 Cr 2 O 7 . The doses were calculated based upon the concentration of Cr contained in the 20 mg/kg dose of CrO 3 (positive control) and on the published genotoxic doses reported for Cr compounds ([Cr] = 10 mg/kg ± 1/3) according to the OECD and EPA guidelines (Dubey et al, 2022;EPA, 1998;Fang et al, 2014;García-Rodríguez, Santiago-Moreno, et al, 2023;Itoh & Shimada, 1996;OECD, 2016;Sawicka et al, 2021;Wang et al, 2006).…”

“…The group treated with 20 mg/kg CrO 3 via i.p. injection was designated as the positive control in all protocols based upon historical data from our laboratory and previous studies, which demonstrated a significant increase in MN levels under the same working conditions (García-Rodríguez et al, 2001, 2013García-Rodríguez, Santiago-Moreno, et al, 2023). The evaluation criteria and experimental conditions were established in accordance with the Organisation for Economic Cooperation and Development (OECD) guidelines (Test No.…”

“…One-way ANOVA: *p < 0.05 versus control. (García-Rodríguez, L opez-Santiago & Altamirano-Lozano, 2021; García- Rodríguez, Serrano-Reyes et al, 2001;García-Rodríguez, Santiago- Moreno, et al, 2023). Conversely, K 2 CrO 4 exhibited the least amount of genotoxicity among the tested compounds.…”