Staining of demineralized cartilage. I. Alcoholic versus aqueous demineralization at neutral and acidic pH.

Demineralization of cartilage with alcoholic EDTA provides cartilage staining that is no better, as measured by scanning microdensitometry, than that of adequately fixed specimens demineralized with aqueous EDTA. Aqueous EDTA is a faster demineralizing agent than alcoholic EDTA. Certain fixatives can preserve maximal proteoglycan staining in articular cartilage even with subsequent rapid demineralization in formate buffer at pH 3.3. Although alcoholic formalin fixation provided optimum quantitative cartilage staining, cetylpyridinium chloride (CPC) in aqueous buffered formalin improved cellular detail, but CPC partially suppressed matrix staining.