Topographical distribution of sulphated glycosaminoglycans in human temporomandibular joint disks. A histochemical study of an autopsy material.

The distribution of sulphated glycosaminoglycans (GAG's) in the human temporomandibular joint disk and its relationship to sex, age and osteoarthrosis was studied by histochemical methods in autopsy material from 18 individuals. The disks were embedded in paraffin and frontal sections, 5-7 mu thick, were cut at different levels. Two staining methods were used, toluidine blue at pH 0.5 and alcian blue with different concentrations of MgCl2. The two methods gave comparable results. The sulphated GAG's as represented by metachromatic staining with toluidine blue at pH 0.5 and staining with alcian blue in concentrations of MgCl2 above 0.55-M were found in the central load-bearing part of the disks evenly distributed in the medio-lateral direction. The findings from the alcian blue staining method indicated the presence of sulphated GAG's with characteristics similar to chondroitin/dermatan sulphate and keratan sulphate. The latter finding was most frequent in a surface zone )10-100 mu) located mainly in the central part of the disks. In macroscopically thin areas of the disks judged as early osteoarthrosis a significant reduction in the staining of sulphated GAG's could be observed. No age or sex differences were found in the distribution of GAG's, either in normal or in osteoarthrotic disks.