Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Subscribe

Logo for

PNAS 104 (20): 8287-8292

Copyright © 2007 by the National Academy of Sciences.

From the Cover

BIOLOGICAL SCIENCES / BIOPHYSICS

Müller cells are living optical fibers in the vertebrate retina

Kristian Franze*, Jens Grosche*,{dagger}, Serguei N. Skatchkov{ddagger}, Stefan Schinkinger§, Christian Foja, Detlev Schild||, Ortrud Uckermann*, Kort Travis§, Andreas Reichenbach*,**, and Jochen Guck§,{dagger}{dagger}

*Paul Flechsig Institute of Brain Research, Universität Leipzig, Jahnallee 59, 04109 Leipzig, Germany; {dagger}Interdisciplinary Center of Clinical Research, Inselstrasse 22, 04103 Leipzig, Germany; {ddagger}Center for Molecular Biology and Neuroscience, Department of Biochemistry, School of Medicine, Universidad Central de Caribe, Bayamon, Puerto Rico 00960; §Division of Soft Matter Physics, Department of Physics, Universität Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany; Department of Ophthalmology and Eye Clinic, Universität Leipzig, 04103 Leipzig, Germany; ||Deutsche Forschungsgemeinschaft Molecular Physiology of the Brain Research Center and Department of Neurophysiology and Cellular Biophysics, Universität Göttingen, 37073 Göttingen, Germany; and {dagger}{dagger}Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom

Edited by Luke Lee, University of California, Berkeley, CA, and accepted by the Editorial Board March 27, 2007

Received for publication December 15, 2006.

Abstract: Although biological cells are mostly transparent, they are phase objects that differ in shape and refractive index. Any image that is projected through layers of randomly oriented cells will normally be distorted by refraction, reflection, and scattering. Counterintuitively, the retina of the vertebrate eye is inverted with respect to its optical function and light must pass through several tissue layers before reaching the light-detecting photoreceptor cells. Here we report on the specific optical properties of glial cells present in the retina, which might contribute to optimize this apparently unfavorable situation. We investigated intact retinal tissue and individual Müller cells, which are radial glial cells spanning the entire retinal thickness. Müller cells have an extended funnel shape, a higher refractive index than their surrounding tissue, and are oriented along the direction of light propagation. Transmission and reflection confocal microscopy of retinal tissue in vitro and in vivo showed that these cells provide a low-scattering passage for light from the retinal surface to the photoreceptor cells. Using a modified dual-beam laser trap we could also demonstrate that individual Müller cells act as optical fibers. Furthermore, their parallel array in the retina is reminiscent of fiberoptic plates used for low-distortion image transfer. Thus, Müller cells seem to mediate the image transfer through the vertebrate retina with minimal distortion and low loss. This finding elucidates a fundamental feature of the inverted retina as an optical system and ascribes a new function to glial cells.

Key Words: fiberoptic plate • glial cells • refractive index • light guides • optical trap

Author contributions: K.F. and J. Grosche contributed equally to this work; K.F., S.N.S., S.S., D.S., K.T., A.R., and J. Guck designed research; K.F., J. Grosche, S.N.S., S.S., and O.U. performed research; C.F. contributed new reagents/analytic tools; K.F., J. Grosche, S.N.S., and K.T. analyzed data; and K.F., D.S., A.R., and J. Guck wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission. L.L. is a guest editor invited by the Editorial Board.

This article contains supporting information online at www.pnas.org/cgi/content/full/0611180104/DC1.

**To whom correspondence should be addressed. E-mail: reia{at}medizin.uni-leipzig.de

© 2007 by The National Academy of Sciences of the USA

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ligand-functionalized nanoparticles target endothelial cells in retinal capillaries after systemic application.
K. Pollinger, R. Hennig, A. Ohlmann, R. Fuchshofer, R. Wenzel, M. Breunig, J. Tessmar, E. R. Tamm, and A. Goepferich (2013)
PNAS 110, 6115-6120
   Abstract »    Full Text »    PDF »
Photonic Crystal Light Collectors in Fish Retina Improve Vision in Turbid Water.
M. Kreysing, R. Pusch, D. Haverkate, M. Landsberger, J. Engelmann, J. Ruiter, C. Mora-Ferrer, E. Ulbricht, J. Grosche, K. Franze, et al. (2012)
Science 336, 1700-1703
   Abstract »    Full Text »    PDF »
Optical Coherence Tomographic Reflectivity of Photoreceptors beneath Cystoid Spaces in Diabetic Macular Edema.
T. Murakami, K. Nishijima, T. Akagi, A. Uji, T. Horii, N. Ueda-Arakawa, Y. Muraoka, and N. Yoshimura (2012)
Invest. Ophthalmol. Vis. Sci. 53, 1506-1511
   Abstract »    Full Text »    PDF »
High-Resolution Photoreceptor Imaging in Idiopathic Macular Telangiectasia Type 2 Using Adaptive Optics Scanning Laser Ophthalmoscopy.
S. Ooto, M. Hangai, K. Takayama, N. Arakawa, A. Tsujikawa, H. Koizumi, S. Oshima, and N. Yoshimura (2011)
Invest. Ophthalmol. Vis. Sci. 52, 5541-5550
   Abstract »    Full Text »    PDF »
Radial Glia: Progenitor, Pathway, and Partner.
M. Sild and E. S. Ruthazer (2011)
Neuroscientist 17, 288-302
   Abstract »    PDF »
Reactive glial cells: increased stiffness correlates with increased intermediate filament expression.
Y.-B. Lu, I. Iandiev, M. Hollborn, N. Korber, E. Ulbricht, P. G. Hirrlinger, T. Pannicke, E.-Q. Wei, A. Bringmann, H. Wolburg, et al. (2011)
FASEB J 25, 624-631
   Abstract »    Full Text »    PDF »
Defective Formation of the Inner Limiting Membrane in Laminin {beta}2- and {gamma}3-Null Mice Produces Retinal Dysplasia.
G. Pinzon-Duarte, G. Daly, Y. N. Li, M. Koch, and W. J. Brunken (2010)
Invest. Ophthalmol. Vis. Sci. 51, 1773-1782
   Abstract »    Full Text »    PDF »
Functions of Mature Mammalian Astrocytes: A Current View.
H. K. Kimelberg (2010)
Neuroscientist 16, 79-106
   Abstract »    PDF »
NEUROSCIENCE: A New Glance at Glia.
A. Reichenbach and T. Pannicke (2008)
Science 322, 693-694
   Abstract »    Full Text »    PDF »
Confocal Blue Reflectance Imaging in Type 2 Idiopathic Macular Telangiectasia.
P. Charbel Issa, T. T. J. M. Berendschot, G. Staurenghi, F. G. Holz, and H. P. N. Scholl (2008)
Invest. Ophthalmol. Vis. Sci. 49, 1172-1177
   Abstract »    Full Text »    PDF »

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882