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Imagerie du collagène par microscopie multiphotonique.

Abstract : The development of new tools and new techniques for biology and Medicine has always been an engine for research in microscopy. The first microscopes Antony von Leeuwenhoek enabled in 1677 discovered bacteria, sperm and red blood cells and today we seek to visualize intracellular processes, protein interaction, the interaction of cells in tissue ... Each year new techniques appear to show smaller, more specific, more physiological. The optics laboratory and the biosciences in which I conducted my dissertation focuses particularly multiphoton microscopy. This type of microscopy, who re- posed on the nonlinear interactions between matter and light, is mainly used today to follow fluorescent markers in tissues through the process of fluo- rescence in two-photon excitation. As such, it serves to supplement the confocal microscopy to view phenomena penetration depths that are inaccessible and allows to work across a fabric. However, multiphoton microscopy not limited to fluorescence excitation two photons, and it also gives access to nonlinear processes such as harmonic generation or the anti-Stokes Raman emission stimulated. These nonlinear interactions are still poorly used in biology and are subject Research in our laboratory. A non-linear processes studied in the laboratory is the second generation of har- Tableware (SHG). This was highlighted in 1961 by P. A. Franken [1] in crystals nonlinear and is widely used to double the frequency of lasers. In 1979, the trial- above has been applied in biology by Samuel Roth and Isaac Freund [2] on the tendons of rats which the organization of collagen yields the nonlinear effect. Almost thirty years have since this experiment, but the second-harmonic generation by collagen remains poorly understood. In addition, although many studies have shown the potential of this technique, it remains little used by biologists. This thesis, under the direction of Marie-Claire Schanne-Klein, wants to answer several questions: - What is the role of the organization of collagen in the submicrometer generation second harmonic signal? - What can make this technique in the visualization of collagen compared to other existing techniques? - What is the relevance of this technique to address biological problems cal? We focused on fibrosis is an abnormal accumulation of collagen tissues. A previous thesis done in our laboratory by Ana-Maria Pena avai already shown the potential of second harmonic generation to assess the severity of pulmonary fibrosis induced by bleomycin. However, these studies in collaboration tion with the pulmonology department of the Bichat hospital remained in a state demonstration principle. We then initiated a close collaboration with a team of nephro logues composed of Pierre Louis Tharaux, Monica and Cecilia Hernest Fligny (Cardiovascula Research Center INSERM U689 Lariboisière, France) working on the phenomenon mena of fibrosis in the kidney, and we applied the second-generation microscopy Harmonic this biomedical problem. In this manuscript, the first chapter introduces the biological concepts on collagen and fibrosis necessary for understanding the rest. The second chapter presents the various visualization techniques of collagen, emphasizes the principles and the device multiphoton microscopy and finally develops a model of signal generation is cond harmonic collagen observed by microscopy. We then in third chapter a methodology for quantifying renal fibrosis, we validate known a murine model of renal fibrosis. The last chapter is devoted to the application our methodology to various biological problems related to renal fibrosis.
keyword : Collagène Fibrose
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Contributor : Ecole Polytechnique <>
Submitted on : Wednesday, July 21, 2010 - 11:25:42 AM
Last modification on : Wednesday, January 23, 2019 - 10:28:59 AM
Long-term archiving on: : Friday, October 22, 2010 - 3:29:44 PM


  • HAL Id : pastel-00004540, version 1



Mathias Strupler. Imagerie du collagène par microscopie multiphotonique.. Physique [physics]. Ecole Polytechnique X, 2008. Français. ⟨pastel-00004540⟩



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