The supravital staining of osteoclasts with neutral-red: their distribution on the parietal bone of normal growing mice, and a comparison with the mutants grey-lethal and hydrocephalus-3

Abstract

Abstract It is shown that the osteoclasts can be supravitally stained with neutral-red so that they are clearly visible under the dissecting microscope. Their distribution on the parietal bone of normal mice at several ages from birth to 28 days and the detailed appearance of neutral-red stained osteoclasts is described. It is shown that the staining reaction varies between individual cells, and some evidence is presented as to the relation of the neutral-red granules to cytoplasmic inclusions and to the Golgi apparatus. The bearing of the data on the origin and fate of osteoclasts is discussed. It is suggested that some of the small osteoclasts arise by separation from larger ones. Preliminary experiments on the application of the method to other parts of the skeleton by injection of the dye are described. The distribution of osteoclasts on the parietal bone of the grey-lethal and hydrocephalus-3 mutants is compared with the normal and the occurrence of giant osteoclasts in the grey-lethal is noted. A comparison of the normal and the grey-lethal by osteoclast counts is reported, and the accuracy of the method assessed. It is shown that the grey-lethal is deficient in number of osteoclasts, and possibly in the amount of osteoclast material. The distribution of osteoclast size in the normal and grey-lethal is compared. Some critical suggestions are put forward concerning the influence of mechanical factors in cranial growth, and the bearing of the present data on the problem is considered. Emphasis is laid on the tendency for a normal pattern of osteoclasts to be maintained even when the mechanical conditions are probably abnormal.