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da Cruz IBM, de Afonso Bonotto NC, Turra BO, Teixeira CF, Azzolin VF, Ribeiro EAM, Piccoli JDCE, Barbisan F. Rotenone-exposure as cytofunctional aging model of human dermal fibroblast prior replicative senescence. Toxicol In Vitro 2023:105637. [PMID: 37394047 DOI: 10.1016/j.tiv.2023.105637] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/04/2023]
Abstract
Rotenone (Ro), causes superoxide imbalance by inhibiting complex I of the mitochondrial electron transport chain, being able to serve as a model for functional skin aging by inducing cytofunctional changes in dermal fibroblasts prior to proliferative senescence. To test this hypothesis, we conducted an initial protocol to select a concentration of Ro (0.5, 1, 1.5, 2, 2.5, and 3 μM) that would induce the highest levels of the aging marker beta-galactosidase (β-gal) in human dermal HFF-1 fibroblasts after 72 h of culture, as well as a moderate increase in apoptosis and partial G1 arrestment. We evaluated whether the selected concentration (1 μM) differentially modulated oxidative and cytofunctional markers of fibroblasts. Ro 1.0 μM increased β-gal levels and apoptosis frequency, decreased the frequency of S/G2 cells, induced higher levels of oxidative markers, and presented a genotoxic effect. Fibroblasts exposed to Ro showed lower mitochondrial activity, extracellular collagen deposition, and fewer fibroblast cytoplasmic connections than controls. Ro triggered overexpression of the gene associated with aging (MMP-1), downregulation genes of collagen production (COL1A, FGF-2), and cellular growth/regeneration (FGF-7). The 1 μM concentration of Ro could serve as an experimental model for functional aging fibroblasts prior to replicative senescence. It could be used to identify causal aging mechanisms and strategies to delay skin aging events.
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Affiliation(s)
- Ivana Beatrice Mânica da Cruz
- Postgraduate Program of Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Postgraduate Program of em Gerontology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Santa Maria, RS, Brazil d Open University of the Third Age, State University of Amazonas, Manaus, AM, Brazil
| | - Nathália Cardoso de Afonso Bonotto
- Postgraduate Program of Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Postgraduate Program of em Gerontology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Bárbara Osmarin Turra
- Postgraduate Program of Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Santa Maria, RS, Brazil d Open University of the Third Age, State University of Amazonas, Manaus, AM, Brazil
| | - Cibele Ferreira Teixeira
- Postgraduate Program of Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Verônica Farina Azzolin
- Postgraduate Program of em Gerontology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Santa Maria, RS, Brazil d Open University of the Third Age, State University of Amazonas, Manaus, AM, Brazil
| | - Ednea Aguiar Maia Ribeiro
- Santa Maria, RS, Brazil d Open University of the Third Age, State University of Amazonas, Manaus, AM, Brazil
| | | | - Fernanda Barbisan
- Postgraduate Program of Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Postgraduate Program of em Gerontology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Santa Maria, RS, Brazil d Open University of the Third Age, State University of Amazonas, Manaus, AM, Brazil.
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Pfuhler S, Downs TR, Hewitt NJ, Hoffmann S, Mun GC, Ouedraogo G, Roy S, Curren RD, Aardema MJ. Validation of the 3D reconstructed human skin micronucleus (RSMN) assay: an animal-free alternative for following-up positive results from standard in vitro genotoxicity assays. Mutagenesis 2021; 36:1-17. [PMID: 33544138 PMCID: PMC8081377 DOI: 10.1093/mutage/geaa035] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 11/25/2020] [Indexed: 11/13/2022] Open
Abstract
In vitro test batteries have become the standard approach to determine the genotoxic potential of substances of interest across industry sectors. While useful for hazard identification, standard in vitro genotoxicity assays in 2D cell cultures have limited capability to predict in vivo outcomes and may trigger unnecessary follow-up animal studies or the loss of promising substances where animal tests are prohibited or not desired. To address this problem, a team of regulatory, academia and industry scientists was established to develop and validate 3D in vitro human skin-based genotoxicity assays for use in testing substances with primarily topical exposure. Validation of the reconstructed human skin micronucleus (RSMN) assay in MatTek Epi-200™ skin models involved testing 43 coded chemicals selected by independent experts, in four US/European laboratories. The results were analysed by an independent statistician according to predefined criteria. The RSMN assay showed a reproducibly low background micronucleus frequency and exhibited sufficient capacity to metabolise pro-mutagens. The overall RSMN accuracy when compared to in vivo genotoxicity outcomes was 80%, with a sensitivity of 75% and a specificity of 84%, and the between- and within-laboratory reproducibility was 77 and 84%, respectively. A protocol involving a 72-h exposure showed increased sensitivity in detecting true positive chemicals compared to a 48-h exposure. An analysis of a test strategy using the RSMN assay as a follow-up test for substances positive in standard in vitro clastogenicity/aneugenicity assays and a reconstructed skin Comet assay for substances with positive results in standard gene mutation assays results in a sensitivity of 89%. Based on these results, the RSMN assay is considered sufficiently validated to establish it as a ‘tier 2’ assay for dermally exposed compounds and was recently accepted into the OECD’s test guideline development program.
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Affiliation(s)
| | | | | | | | - Greg C Mun
- Institute for In Vitro Sciences, Inc., Gaithersburg, MD, USA
| | | | | | - Rodger D Curren
- Institute for In Vitro Sciences, Inc., Gaithersburg, MD, USA
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