Aletéia M M Fernandes1,2, Polyana G F Vilela3, Marcia C Valera4, Carola Bolay5, Karl Anton Hiller5, Helmut Schweikl5, Gottfried Schmalz6,7. 1. Department of Health Sciences, Endodontics Division, Nove de Julho University (UNINOVE), São Paulo, Brazil. 2. Department of Health Sciences, Anatomy and Pathology Division, Anhanguera University, Vergueiro, 235/249-Liberdade, São Paulo, SP, 01504-000, Brazil. 3. Department of Bioscience and Oral Diagnosis, Microbiology Division, São José dos Campos Dental School, State University of São Paulo, UNESP, Av. Eng. Francisco José Longo, 777-Jardim Sao Dimas, São José dos Campos, SP, 12245-000, Brazil. 4. Department of Restorative Dentistry, Endodontic Division, São José dos Campos Dental School, State University of São Paulo UNESP, Av. Eng. Francisco José Longo, 777-Jardim Sao Dimas, São José dos Campos, SP, 12245-000, Brazil. 5. Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany. 6. Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany. Gottfried.Schmalz@ukr.de. 7. Department of Periodontology, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland. Gottfried.Schmalz@ukr.de.
Abstract
OBJECTIVES: The aim of this study was to evaluate the cytotoxicity and the influence of bleaching agents on immunologically cell surface antigens of murine macrophages in vitro. MATERIALS AND METHODS: RAW 264.7 cells were exposed to bleaching gel extracts (40% hydrogen peroxide or 20% carbamide peroxide) and different H2O2 concentrations after 1 and 24-h exposure periods and 1-h exposure and 23-h recovery. Tests were performed with and without N-acetyl cysteine (NAC) and buthionine sulfoximine (BSO). Cell viability was determined by MTT assay. The expression of surface markers CD14, CD40, and CD54 with and without LPS stimulation was detected by flow cytometry, while the production of TNF-α was measured by ELISA. Statistical analysis was performed using the Mann-Whitney U test (α = 0.05). RESULTS: Extracts of bleaching agents were cytotoxic for cells after a 1-h exposure; cells could not recover after 24 h. This effect can be mitigated by the antioxidant NAC and increased by BSO, an inhibitor of glutathione (GSH) synthesis. LPS stimulated expression of all surface markers and TNF-α production. Exposure to bleaching agent extracts and H2O2 leads to a reduction of TNF-α, CD14, and CD40 expression, while the expression of CD54 was upregulated at non-cytotoxic concentrations. Whereas NAC reduced this effect, it was increased in the presence of BSO. CONCLUSIONS: Extracts of bleaching agents were irreversibly cytotoxic to macrophages after a 1-h exposure. Only the expression of CD54 was upregulated. The reactions are mediated by the non-enzymatic antioxidant GSH. CLINICAL RELEVANCE: The addition of an antioxidant can downregulate unfavorable effects of dental bleaching.
OBJECTIVES: The aim of this study was to evaluate the cytotoxicity and the influence of bleaching agents on immunologically cell surface antigens of murine macrophages in vitro. MATERIALS AND METHODS: RAW 264.7 cells were exposed to bleaching gel extracts (40% hydrogen peroxide or 20% carbamide peroxide) and different H2O2 concentrations after 1 and 24-h exposure periods and 1-h exposure and 23-h recovery. Tests were performed with and without N-acetyl cysteine (NAC) and buthionine sulfoximine (BSO). Cell viability was determined by MTT assay. The expression of surface markers CD14, CD40, and CD54 with and without LPS stimulation was detected by flow cytometry, while the production of TNF-α was measured by ELISA. Statistical analysis was performed using the Mann-Whitney U test (α = 0.05). RESULTS: Extracts of bleaching agents were cytotoxic for cells after a 1-h exposure; cells could not recover after 24 h. This effect can be mitigated by the antioxidant NAC and increased by BSO, an inhibitor of glutathione (GSH) synthesis. LPS stimulated expression of all surface markers and TNF-α production. Exposure to bleaching agent extracts and H2O2 leads to a reduction of TNF-α, CD14, and CD40 expression, while the expression of CD54 was upregulated at non-cytotoxic concentrations. Whereas NAC reduced this effect, it was increased in the presence of BSO. CONCLUSIONS: Extracts of bleaching agents were irreversibly cytotoxic to macrophages after a 1-h exposure. Only the expression of CD54 was upregulated. The reactions are mediated by the non-enzymatic antioxidant GSH. CLINICAL RELEVANCE: The addition of an antioxidant can downregulate unfavorable effects of dental bleaching.
Authors: Letícia Cunha Amaral Gonzaga de Almeida; Diana Gabriela Soares; Marjorie Oliveira Gallinari; Carlos Alberto de Souza Costa; Paulo Henrique Dos Santos; André Luiz Fraga Briso Journal: Clin Oral Investig Date: 2014-07-19 Impact factor: 3.573
Authors: Ramune Reliene; Julianne M Pollard; Zhanna Sobol; Benedicte Trouiller; Richard A Gatti; Robert H Schiestl Journal: Mutat Res Date: 2009-03-13 Impact factor: 2.433