title: Toxic effects of a modified montmorillonite clay on the human intestinal cell line Caco-2.
abstract: The incorporation of the natural mineral clay montmorillonite into polymeric systems enhances their barrier properties as well as their thermal and mechanical resistance, making them suitable for a wide range of industrial applications, e.g., in the food industry. Considering humans could easily be exposed to these clays due to migration into food, toxicological and health effects of clay exposure should be studied. In the present work, the cytotoxic effects induced by two different clays (the unmodified clay Cloisite(®) Na(+) , and the organically modified Cloisite(®) 30B) on Caco-2 cells were studied after 24 and 48 h of exposure. The basal cytotoxicity endpoints assessed were total protein content, neutral red uptake and a tetrazolium salt reduction. Our results showed that only Cloisite(®) 30B induced toxic effects. Therefore, the effects of subcytotoxic concentrations of this clay on the generation of intracellular reactive oxygen species, glutathione content and DNA damage (comet assay) were investigated. Results indicate that oxidative stress may be implicated in the toxicity induced by Closite(®) 30B, in regards of the increases in intracellular reactive oxygen species production and glutathione content at the highest concentration assayed, while no damage was observed in DNA. The most remarkable morphological alterations observed were dilated cisternae edge in the Golgi apparatus and nucleolar segregation, suggesting impairment in the secretory functions, which could be related to inhibition in the synthesis of proteins.
authors.affiliation: Department of Toxicology, Faculty of Pharmacy, University of Seville, Profesor García González n°2, 41012, Seville, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Maisanaba
authors.forename: Daniel
authors.initials: D
authors.lastname: Gutiérrez-Praena
authors.forename: Silvia
authors.initials: S
authors.lastname: Pichardo
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Moreno
authors.forename: María
authors.initials: M
authors.lastname: Jordá
authors.forename: Ana M
authors.initials: AM
authors.lastname: Cameán
authors.forename: Susana
authors.initials: S
authors.lastname: Aucejo
authors.forename: Angeles
authors.initials: A
authors.lastname: Jos
mesh_terms: D000538:Aluminum Silicates / Q000633:toxicity*; D001546:Bentonite / Q000633:toxicity*; D018938:Caco-2 Cells; D002466:Cell Nucleolus / Q000378:metabolism / Q000648:ultrastructure; D048430:Cell Shape / Q000187:drug effects; D000077215:Clay; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors
chemical_list: D000538:Aluminum Silicates; D017382:Reactive Oxygen Species; D001546:Bentonite; D005978:Glutathione; D000077215:Clay
keywords: Cloisite®; cell culture; clays; cytotoxicity; morphology; oxidative stress