Effects of Oxidation upon Alcian Blue Staining of Acid Mucopolysaccharides.

Since Steedman ( 1950) has introduced it into histochemistry, alcian blue has been advocated to reveal a staining selectivity which depends upon the presence of acidic groups in mucopolysaccharides (Mowry, 1956; Pearse, 1960). As a plausible ground of this concept the fact has been presented that the alcian blue staining of polysaccharides can be increased in intensity, when acidic groups are introduced artificially into the substances. A series of subsequent histochemical data obtained by Spicer ( 1960), Spicer and Meyer ( 1960) and by myself (Yamada, 1962 and 1963 a) have, however, not necessarily been on the side of the above concept and some types of tissue mucopolysaccharides have been shown to rather decline in alcian blue staining intensity, even after acidic groups are introduced experimentally into them. Moreover. my recent studies on the alcian blue stainability of sulfated polysaccharides of either proposed or known chemical structure have indicated that the selectivity of the basic dye is not always dependent exclusively on the presence of acidic groups in polysaccharides, but their appropriate hydroxyl groups can influence their aldan blue staining (Yamada, 1963 b). In the present study, I have examined the alcian blue staining of several types of tissue acid mucopolysaccharides following oxidation which is known to introduce carboxyl groups into the substances, and attempted thus to obtain further evidence which helps to understand the staining mechanism of this basic dye.