A Simple Method for Removing the Resin from Epoxy-embedded Tissue

Epoxy resins were first used as embedd ing media for electron microscopy by MaalCe and BirchAndersen (1) and Glauer t and Glauer t (2) and have since been employed extensively in Grea t Bri tain by Huxley (3) and Rober tson (4). Recen t improvements in processing and embedd ing techniques by Luft (5) and Finck (6) have led to their acceptance in many laboratories throughout the Uni t ed States. In correlated studies using electron and l ight microscopy it is usually necessary to remove the embedd ing mater ia l from the thick sections dest ined for convent ional l ight microscopy before they yield opt imal results in cellular detail and s taining qualities. Both xylol and acetone are excellent and rapid solvents for methacrylate , and removal of this plastic and subsequent staining for l ight microscopy are simple procedures (Bencosme et al., 7). Epoxy resins, however, are not soluble in s tandard organic solvents. Fisch and Hofmann (8) have studied the controlled chemical degrada t ion into soluble components of epoxy resins cured with phthal ic anhydride. Applying some of their findings we have developed a suitable solvent for use in tissue-resin systems.