Histochemical observations on the ribonucleic acid and glycoprotein content of the osteoclasts of the normal and ia rat

Abstract

The histochemically demonstrable ribonucleic acid (RNA) and glycoprotein content of the osteoclast has been investigated in both normal and ia rats. The osteoclasts of the normal animal vary considerably in the amount of RNA present in their cytoplasm. Thus, the cells can be arranged in a series based on a progressive decrease or increase in RNA content. The majority of the osteoclasts contain an oxyphilic and pyroninophobic zone of variable width adjacent to the bone. It is suggested that the variation in RNA content might possibly be correlated with the functional state of the cell. The osteoclasts of the ia rat differ from those of the normal rat in the pattern of their RNA distribution. The predominating number of cells lack the oxyphilic, pyroninophobic zone adjacent to the bone. Since comparable results were obtained with methylene blue, pyronin and gallocyanin, it is felt that the overall decrease in thionin-positive material may be due to dye-protein interactions. The glycoprotein of the normal osteoclast is confined to sparsely scattered granules. A marked increase in the number of glycoprotein granules occurs in many of the ia osteoclasts. The significance of this increase is not apparent.