title: Retinal glial (Müller ) cells: sensing and responding to tissue stretch.
abstract: OBJECTIVE
  To test whether Müller glial cells sense, and respond to, mechanical tension in the retina.
  
  
  METHODS
  A device was designed to stretch the retina at right angles to its surface, across retinal layers. Pieces of retina were mounted between two hollow tubes, and uniaxial force was applied to the tissue using a micrometer-stepping motor. Müller cells were selectively stained with the fluorescent, calcium-sensitive dye X-Rhod-1 and were monitored in real time during retinal stretch in vitro. Immunohistochemistry was used to study protein levels and activation of intracellular pathways in stretched retinas.
  
  
  RESULTS
  Müller cells responded acutely with transient increases in fluorescence during stretch, indicative of increased intracellular calcium levels. All the Müller cells elongated uniformly, and there was no apparent difference between retinal layers in resistance against mechanical deformation. After stretch, Müller cells showed fast activation of extracellular signal-regulated kinase (after 15 minutes), upregulation of transcription factor c-Fos (after 1 hour), and basic fibroblast growth factor (after 3 hours). No changes in intermediate filament protein expression were observed in Müller cells up to 3 hours after stretch.
  
  
  CONCLUSIONS
  A novel technique was developed for real-time monitoring of Müller cells during retinal stretch, which allowed the identification of Müller cells as a mechanoresponsive cell type. Mechanical stress triggers molecular responses in Müller cells that could prevent retinal damage.
authors.affiliation: Department of Pathophysiology of Neuroglia, Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany.
authors.forename: Niclas
authors.initials: N
authors.lastname: Lindqvist
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Joachim
authors.initials: J
authors.lastname: Zajadacz
authors.forename: Kristian
authors.initials: K
authors.lastname: Franze
authors.forename: Andreas
authors.initials: A
authors.lastname: Reichenbach
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D007150:Immunohistochemistry; D008465:Mechanoreceptors / Q000378:metabolism*; D040542:Mechanotransduction, Cellular / Q000502:physiology; D008856:Microscopy, Fluorescence; D009457:Neuroglia / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D005456:Fluorescent Dyes; D016760:Proto-Oncogene Proteins c-fos; D016222:Fibroblast Growth Factor 2; D048049:Extracellular Signal-Regulated MAP Kinases; D002118:Calcium