Histochemical study of human epiphyseal cartilage

A histochemical study, based on the distribution and state of aggregation of the macromolecular components of the matrix, was performed on epiphyseal cartilage from the femur, tibia and fibula of subjects aged between 11 and 14 years. Different histochemical behaviour was demonstrated between the longitudinal septa, which calcify, and the transverse septa, which are broken down without any mineral deposition. In these two sectors of the extracellular matrix, proteoglycans, glycoproteins and phospholipids are distributed and aggregated differently, as was also shown by extraction of the cartilage in guanidine chloride. The calcified cartilaginous matrix and the osteoid margins are intensely PAS positive, probably due to glycoproteins involved in the process of laying down mineral deposits. PAS positive granulations, resistant to digestion with alpha-amylase, and probably of lysosomal nature, are present between the capillary loops, and the transverse septa may be involved in the process of degradation of the cartilaginous matrix in which no minerals have been deposited.