Chemical Clearing and Dehydration of GFP Expressing Mouse Brains

PLoS One. 2012;7(3):e33916. doi: 10.1371/journal.pone.0033916. Epub 2012 Mar 30.

Abstract

Generally, chemical tissue clearing is performed by a solution consisting of two parts benzyl benzoate and one part benzyl alcohol. However, prolonged exposure to this mixture markedly reduces the fluorescence of GFP expressing specimens, so that one has to compromise between clearing quality and fluorescence preservation. This can be a severe drawback when working with specimens exhibiting low GFP expression rates. Thus, we screened for a substitute and found that dibenzyl ether (phenylmethoxymethylbenzene, CAS 103-50-4) can be applied as a more GFP-friendly clearing medium. Clearing with dibenzyl ether provides improved tissue transparency and strikingly improved fluorescence intensity in GFP expressing mouse brains and other samples as mouse spinal cords, or embryos. Chemical clearing, staining, and embedding of biological samples mostly requires careful foregoing tissue dehydration. The commonly applied tissue dehydration medium is ethanol, which also can markedly impair GFP fluorescence. Screening for a substitute also for ethanol we found that tetrahydrofuran (CAS 109-99-9) is a more GFP-friendly dehydration medium than ethanol, providing better tissue transparency obtained by successive clearing. Combined, tetrahydrofuran and dibenzyl ether allow dehydration and chemical clearing of even delicate samples for UM, confocal microscopy, and other microscopy techniques.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism*
  • Dehydration
  • Furans / chemistry
  • Furans / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism*
  • Mice
  • Mice, Transgenic
  • Phenyl Ethers / chemistry
  • Phenyl Ethers / metabolism
  • Solvents / chemistry
  • Solvents / metabolism

Substances

  • Furans
  • Phenyl Ethers
  • Solvents
  • Green Fluorescent Proteins
  • dibenzyl ether
  • tetrahydrofuran