Iodoacetate poisoning of the rat retina. I. Production of retinal degeneration.

IT is now well established that retinal degeneration can be produced in several species of laboratory animals by intravenous injection of sodium iodoacetate (Schubert and Bornschein, 1951; Noell, 1952; Berardinis, 1953; Karli, 1954; Rabinovitch, Mota, and Yoneda, 1954; Babel and Ziv, 1956). Thus, Noell (1952) described a destruction of the visual cells in rabbits, cats, and monkeys after repeated doses, and drew attention to the close similarity between the experimental condition and retinitis pigmentosa in man (Noell, 1953). Most workers have used rabbits for these studies, but Rabinovitch and others (1954) recorded the same result in chickens. So far the rat has been found to be an unsatisfactory animal for such experiments; Rabinovitch and his co-workers (1954) failed to obtain retinal degeneration in this species after repeated sub-lethal doses. Noell (1952) has remarked on the difficulty of finding a single sub-lethal dose which would produce histologically recognizable damage to the retina. Most of his studies in rabbits involved the use of repeated doses of 15 to 20 mg./kg. body weight (12 mg./kg. in the cat). In this laboratory, however, it has been found possible to produce histological damage in the rabbit by giving a single injection of40 mg./kg. In order to achieve this without killing the animal it was necessary to administer the dosein at least 10 ml. saline over a period of about 20 minutes (Tansley, 1955). The present observations arose out of attempts to produce retinal degeneration in the rat for metabolic studies. We also failed to achieve this in the rat with a single sub-lethal dose and therefore tried other procedures.