The reaction of osmium tetroxide with tissue components

Abstract

A study was made of the effects of OsO 4 in aqueous and non-polar solutions on tissue sections and on some pure compounds. Aqueous solutions of OsO 4 inhibit the acidophilia of tissue constituents and the basophilia of gastro-intestinal mucus. Treatment of tissue sections by OsO 4 in non-polar solvents results in a histological picture which is similar to that obtained in electron micrographs of tissues fixed in solutions of OsO 4. The evidence presented indicates that OsO 4 reacts with tissue constituents at least in three different manners: ( a) with some compounds black precipitates are formed in aqueous solutions; ( b) with other compounds black precipitates are formed only in the absence of water or with incomplete hydration; ( c) with still other compounds which react with OsO 4, no precipitation of osmium occurs. Glucosamine (and glucosamine-containing polysaccharides) were found to be compounds which in the non-hydrated state form black precipitates with OsO 4-oxidant mixtures and not with OsO 4 alone. It is considered probable that a hexosamine-containing compound is made available for reacting during demyelination and is responsible for the Marchi staining.