This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Riou, C. Articles by Rousset, B. Search for Related Content PubMed PubMed Citation Articles by Riou, C. Articles by Rousset, B. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB CYCLOHEXIMIDE HYDROGEN PEROXIDE

Susceptibility of Differentiated Thyrocytes in Primary Culture to Undergo Apoptosis after Exposure to Hydrogen Peroxide: Relation with the Level of Expression of Apoptosis Regulatory Proteins, Bcl-2 and Bax¹

INSERM, U-369, Faculté de Médecine Lyon-RTH Laennec, 69372 Lyon Cedex 08, France

Address all correspondence and requests for reprints to: Prof. Bernard Rousset, INSERM U-369, rue Guillaume Paradin, Faculté de Médecine Lyon-RTH Laennec, 69372 Lyon Cedex 08, France. E-mail: u369{at}laennec.univ-lyon1.fr

Thyrocytes, that generate and use hydrogen peroxide (H₂O₂) to synthesize thyroid hormones, undergo apoptosis, as do most cell types, when exposed in vitro to H₂O₂. We have studied 1) the kinetics and the amplitude of the apoptotic response to H₂O₂ and 2) the relationship between the extent of the apoptosis-inducing effect of H₂O₂, the H₂O₂ degradation activity, and the level of expression of apoptosis regulatory proteins, Bcl-2 and Bax, in pig thyrocytes in primary culture. Cells were seeded at high density to obtain confluent monolayers and were cultured in the presence of TSH to maintain the expression of differentiation. H₂O₂ (10–300 µM) induced the appearance of cells with fragmented DNA (terminal transferase deoxy-UTP-fluorescein isothiocyanate nick end labeling-positive cells) at a maximum of 3–4 h after H₂O₂ addition and then the detachment of apoptotic cells from the cell monolayer. The proportion of detached cells increased with H₂O₂ concentration and amounted to up to 30% of the initial cell number after 24 h. The transient effect of H₂O₂ was related to its rapid degradation by cells and culture medium components (rate constant, 0.1 min^-1). Iterative additions of H₂O₂ produced cumulative apoptotic waves. The amplitude of the apoptotic response of thyrocytes to H₂O₂ progressively increased with the time of culture, up to 4-fold from days 1–8. This was not related to a change in the capacity of thyrocytes to degrade H₂O₂. During the same period of culture, the Bcl-2 cell content progressively decreased, whereas that of Bax concomitantly increased; thus, the Bcl-2/Bax ratio varied from about 6 on day 1 to 0.5 on day 10. These data show that the susceptibility of thyrocytes to undergo apoptosis increases with the time of culture and that the pronounced changes in the apoptotic status of thyrocytes might be linked to coordinate modifications of the level of expression of pro- and antiapoptotic regulatory proteins.

This article has been cited by other articles:

				Y. Song, N. Driessens, M. Costa, X. De Deken, V. Detours, B. Corvilain, C. Maenhaut, F. Miot, J. Van Sande, M.-C. Many, et al. Roles of Hydrogen Peroxide in Thyroid Physiology and Disease J. Clin. Endocrinol. Metab., October 1, 2007; 92(10): 3764 - 3773. [Abstract] [Full Text] [PDF]

				J. A. Gilbert, A. G. Gianoukakis, S. Salehi, J. Moorhead, P. V. Rao, M. Z. Khan, A. M. McGregor, T. J. Smith, and J. P. Banga Monoclonal pathogenic antibodies to the thyroid-stimulating hormone receptor in Graves' disease with potent thyroid-stimulating activity but differential blocking activity activate multiple signaling pathways. J. Immunol., April 15, 2006; 176(8): 5084 - 5092. [Abstract] [Full Text] [PDF]

				B. Corvilain, L. Collyn, J. van Sande, and J. E. Dumont Stimulation by iodide of H2O2 generation in thyroid slices from several species Am J Physiol Endocrinol Metab, April 1, 2000; 278(4): E692 - E699. [Abstract] [Full Text] [PDF]

				X. De Deken, D. Wang, M.-C. Many, S. Costagliola, F. Libert, G. Vassart, J. E. Dumont, and F. Miot Cloning of Two Human Thyroid cDNAs Encoding New Members of the NADPH Oxidase Family J. Biol. Chem., July 21, 2000; 275(30): 23227 - 23233. [Abstract] [Full Text] [PDF]

				H. Kim, T.-H. Lee, E. S. Park, J. M. Suh, S. J. Park, H. K. Chung, O-Y. Kwon, Y. K. Kim, H. K. Ro, and M. Shong Role of Peroxiredoxins in Regulating Intracellular Hydrogen Peroxide and Hydrogen Peroxide-induced Apoptosis in Thyroid Cells J. Biol. Chem., June 9, 2000; 275(24): 18266 - 18270. [Abstract] [Full Text] [PDF]