Histochemical Studies on the Properties of Both Ceroid and Lipofuscin by Means of the Modified Aldehyde Fuchsin Method

Abstract

So long as Gomori's aldehyde fuchsin (AF) method is tested under the conditions that the AF solution should be used from three to seven days after preparation, two sorts of lipopigments, namely, ceroid and lipofuscin can be discriminated from each other in that the former was moderately positive with the AF method and the latter, almost negative.
By introducing various pre-treatments, such as peracetic acid or periodic acid oxidation followed by methylation to the procedure of the AF method, it was found that the AF-positive finding of ceroid is ascribable to the presence of carboxylic groups of protein low in aqueous solubility.
The presence in lipofuscin of carboxylic groups of protein low in aqueous solubility may be denied, because lipofuscin shows no positive reaction with the AF method.
Ceroid in the lymph node of a rat fed on a vitamin E-deficient diet for about one year, stains somewhat weakly with the AF method, however, this sort of ceroid became intensely positive with the same method after peracetic acid oxidation, because this pigment is regarded as being rich in disulfide groups.
Moreover, an intense coloration of ceroid in the liver as well as in the lymph nodes obtained with the AF method following peracetic acid oxidation can withstand the treatment with a 6-hour,60°C methylation, however, the moderately positive periodic acid-AF reaction of ceroid cannot withstand the same treatment.
This finding may be satisfactorily accounted for by the appearance of sulfonic groups in ceroid obtained by peracetic acid oxidation of disulfide groups.
On the other hand, lipofuscin indicates a moderately positive peracetic acid-and periodic acid-AF reaction whose coloration cannot withstand the treatment with a 6-hour,60°C methylat ion, but a 4-hour,60°C methylation.
From these findings it may be considered that a sort of proteinic groups other than disulfide groups is responsible for the oxidation-AF-positive finding of lipofuscin, and for the periodic acid-AF-positive finding of ceroid.
Besides, acid-fast lipofuscin granules found in the nerve cells both in the human brain and in the brain of rats fed on a vitamin E-deficient diet over one year scarecely stain with the AF method with which ceroid in the Rouget cells gives an intensely positive reaction. On the basis of the above findings the author supports the assumption that they should not be regarded as ceroid, but as a sort of lipofuscin. The entity of yellow pigment contained in fat-granule cells (“gitter cells”) is also discussed.