Accumulation of collagen-containing vacuoles in osteoblasts after administration of colchicine

Embryonic mouse radii were cultured in the presence of colchicine or vinblastine and subsequently examined in the electron microscope. As a result of the administration of these drugs large numbers of vacuoles accumulated in the cytoplasm of the osteoblasts. The electron-dense contents of at least many of the vacuoles most probably consisted of collagen. This conclusion was based on the results of special staining methods and on the similarity of the vacuoles to collagen vacuoles described in the literature. The observations made in this study provide morphological evidence that colchicine and vinblastine disturb the secretion of collagen.