Early ultrastructural alterations in rats after administration of 239Pu-citrate.

Three series of ultrastructural studies are carried out with adult male Sprague Dawley rats injected with 239plutonium citrate. Two groups of rats are used in the first series of experiments. The animals of the first group are injected with 5 x 2.3 KBq while the animals of the second group received 5 x 9.25 KBq. The animals of the second series of experiment are injected with a single dose of 1 KBq while the animals of the third series received 5 x 200 Bq. Seven days after the first injections, animals kidneys of the first series of experiments have serious mitochondrial alterations in the proximal convoluted tubular and glomerular cells. Bone marrow cells have the same type of mitochondrial alterations as the above kidney cells. The affected mitochondria are swollen and have their cristae partially or completely destroyed. Very slight subcellular alterations are noted in the livers. The same type of alterations are observed in the kidney and bone marrow samples of the animals two days after injection of 1 KBq, but 23 days later no more ultrastructural alteration are noticed. No subcellular alterations are observed in the animals of the third series. These observations suggest that the chemical origin of these cellular lesions has to be taken into consideration even if the mass of injected radionuclide is low (2.04-81.6 mg/kg).

[Early ultrastructural lesions of kidney cells after intravenous administration of 239 plutonium citrate in rats]. / Lésions ultrastructurales précoces des cellules rénales après administration intraveineuse de citrate de plutonium 239 chez le rat.

After intravenous administration of (5 x 2.3 kBq and 5 x 9.25 kBq) plutonium citrate in adult male Sprague Dawley rats, their kidneys are withdrawn and prepared for observation under a transmission electron microscope. Seven days after the first injections, deep cellular alterations are observed in the proximal convoluted tubules. These alterations are mainly mitochondrial. The affected mitochondria are of swollen aspect and have their cristae partially or completely destroyed. Nevertheless within the same tubule we observe non altered cells directly in contact with deeply altered cells. In all the cases the lysosomes of the altered cells appear to be perfectly normal. The cell nuclei are mostly unaltered but a few cases of nuclear fragmentation exist. We also notice some architectural modifications in the brush border and in the betacytomembranes of the proximal convoluted tubule. Equally important mitochondrial alterations are also noticed in the different varieties of glomerular cells. We observe no other glomerular alterations. The major subcellular alterations in the proximal convoluted tubules and in the different varieties of glomerular cells deeply contrast with the distal convoluted tubules which are found to be totally unaltered. These mitochondrial alterations may be due to the alpha particle disintegration of plutonium which may either directly react with the mitochondria or, through the products of radiolysis of water react with the mitochondria respiration process. However the direct chemotoxicity of plutonium cannot be neglected.