Phagocytic activity of hyalocytes in postnatal hyaloid artery.

The postnatal hyaloid arteries of rabbits aged between 7 and 21 days were investigated by transmission and scanning electron microscopy. The artery did not yet show significant degenerating processes on the 7th day, but many cells identifiable as hyalocytes were observed in the adventitia on the 10th day. Between 13 and 15 days, the artery began to undergo a marked degeneration. The number of myofilaments decreased in most smooth muscle cells in the media and the cells were transformed, resembling fibroblasts in this cytoplasmic feature. Around 3 weeks, the vascular lumen was completely closed with almost complete loss of the endothelial cells, and the degenerating cellular components were actively phagocytized by the hyalocytes.