Fluoride does not induce DNA breakage in Chinese hamster ovary cells in vitro

Abstract

Fluoride has been widely used in dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury to genetic material. Genotoxicity tests represent an important part of cancer research to assess the risk of potential carcinogens. In the current study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet) assay in vitro. Chinese hamster ovary cells were exposed to sodium fluoride (NaF) at final concentration ranging from 7 to 100 µg/ml for 3 h, at 37°C. The results pointed out that NaF in all concentrations tested did not contribute to DNA damage as depicted by the mean tail moment and tail intensity. These findings are clinically important since they represent an important contribution to a correct evaluation of the potential health risk associated with the exposure to dental agents. DESCRIPTORS: Sodium fluoride; Comet assay; Mutagenicity tests. RESUMO:O flúor tem sido amplamente usado na Odontologia, pois é um agente profilático efetivo e específico contra a cárie dentária. Entretanto, o flúor em excesso pode representar perigos à saúde humana, especialmente por causar agressão ao material genético. Testes de genotoxicidade representam uma importante parte da pesquisa do câncer para a avaliação de risco de possíveis carcinógenos. Neste presente estudo, danos ao DNA associados à exposição ao flúor foram avaliados pelo teste de células individualizadas em gel de agarose (teste do cometa) in vitro. Células de ovário de hamster chinês foram expostas ao fluoreto de sódio (NaF) nas concentrações finais de 7 a 100 µg/ml, durante 3 h, a 37°C. Os resultados mostraram que o NaF não contribuiu para os danos no DNA em todas as concentrações testadas, conforme demonstrado pelas médias do momento da cauda e da intensidade da cauda dos cometas. Esses achados são clinicamente importantes, uma vez que representam uma importante contribuição para a correta avaliação do potencial risco à saúde associada à exposição aos agentes odontológicos. DESCRITORES: Fluoreto de sódio; Ensaio em cometa; Testes de mutagenicidade.

Fluoride modulates preosteoblasts viability and matrix metalloproteinases-2 and -9 activities

“…(17,21). In addition, other authors showed that fluoride does not induce DNA damage (22). In this study it is proposed that F at 10 -3 M might trigger apoptosis by activating caspases signaling pathways.…”

Comparative study of a new composite biomaterial fluor-hydroxyapatite on fibroblast cell line NIH-3T3 by direct test

“…Therefore it is used for osteoporosis treatment (Astern et al 1998). Furthermore, fluoride has been widely used in dentistry as caries prophylactic agents (Ribeiro et al 2004). NaF was the first and still most recommended fluoride compound for fluoridation of drinking water (Ribeiro et al 2006).…”

Genotoxicity and cytotoxicity of mineral trioxide aggregate and calcium enriched mixture cements on L929 mouse fibroblast cells

“…Animal systems may more accurately reflect human metabolism; however, they are expensive and time-consuming (requiring up to 3 years to complete); they are, therefore, not used as a first screen for genotoxicity or carcinogenicity. Thanks to the work of previous investigators, the single-cell, gel (comet) assay has been accepted as a rapid, simple, and reliable method of evaluating the genotoxicity of materials [15][16][17][18][19][20] . The basic principle of this assay is the migration of DNA fragments in an agarose matrix under electrophoresis.…”

“…When viewed under a microscope, cells have the appearance of a comet, with a head (the nuclear region) and a tail containing DNA fragments or strands migrating toward the anode 20) . The studies of Ribeiro and coworkers have demonstrated that the single-cell gel (comet) assay is one of the suitable tools to investigate the genotoxicity of compounds used in dental practice [17][18][19] . Previous studies have demonstrated that MTA, whether gray or white, cannot induce geno-or cytotoxicity in mouse lymphoma or Chinese hamster ovary (CHO) cells, even after exposure to human peripheral lymphocytes ex vivo 20,21) .…”