Phagocytic and digestive activities of retinal pigment epithelium at experimentally produced retinal tears

The present study examined the phagocytic and digestive activities of retinal pigment epithelial cells (RPE cells) at sites of experimentally produced retinal tears, using the phagocytosis of the latex particles by these cells as a measure of phagocytic activity, and their acid phosphatase activity as a measure of their digestive activity. Four days after retinal tear formation, acid phosphatase activity of RPE cells at the site of retinal tears was the same as that of the RPE cells in the surrounding normal retina. However, at one week, four weeks and six months after tear formation, acid phosphatase activity of RPE cells at the site of retinal tears was higher than that of the RPE cells in the surrounding normal retina. Four weeks after retinal tear formation, a latex particle solution was injected onto the retinal tear or subretinally. The RPE cells at the site of retinal tears phagocytized the latex particles earlier than did the RPE cells of the eye which was injected subretinally. At three hours after the injection, the RPE cells at the site of retinal tear had phagocytized more latex particles in their cytoplasm than RPE cells in normal retina. It can be concluded that RPE cells at the site of retinal tear had higher phagocytic and digestive activity than did RPE cells in normal retina.