Distribution of uranium in rats implanted with depleted uranium pellets

Abstract

During the Persian Gulf War, soldiers were injured with depleted uranium (DU) fragments. To assess the potential health risks associated with chronic exposure to DU, Sprague Dawley rats were surgically implanted with DU pellets at 3 dose levels (low, medium and high). Biologically inert tantalum (Ta) pellets were used as controls. At 1 day and 6, 12, and 18 months after implantation, the rats were euthanized and tissue samples collected. Using kinetic phosphorimetry, uranium levels were measured. As early as 1 day after pellet implantation and at all subsequent sample times, the greatest concentrations of uranium were in the kidney and tibia. At all time points, uranium concentrations in kidney and bone (tibia and skull) were significantly greater in the high-dose rats than in the Ta-control group. By 18 months post-implantation, the uranium concentration in kidney and bone of low-dose animals was significantly different from that in the Ta controls. Significant concentrations of uranium were excreted in the urine throughout the 18 months of the study (224 +/- 32 ng U/ml urine in low-dose rats and 1010 +/- 87 ng U/ml urine in high-dose rats at 12 months). Many other tissues (muscle, spleen, liver, heart, lung, brain, lymph nodes, and testicles) contained significant concentrations of uranium in the implanted animals. From these results, we conclude that kidney and bone are the primary reservoirs for uranium redistributed from intramuscularly embedded fragments. The accumulations in brain, lymph nodes, and testicles suggest the potential for unanticipated physiological consequences of exposure to uranium through this route.

Depleted and Natural Uranium: Chemistry and Toxicological Effects

“…Small portions of uranium have also been detected in the lungs and liver (Fulco et al, 2000). Figure 3, as reported by Pellmar et al (1999a), demonstrated the organ distribution of DU following 18 mo of implantation of 4, 10, or 20 DU pellets in SpragueDawley rats. This experiment was repeated using tantalum pellets instead of DU.…”

Uranium modifies or not behavior and antioxidant status in the hippocampus of rats exposed since birth

“…The accumulation of U in the hippocampus suggests that U has a direct neurotoxic effect on the central nervous system. It has previously been shown that U may be toxic to this cerebral structure (Pellmar et al, 1999b). Finally, the lack of any significant effect on oxidative stress by exposure to 10 mg.L -1 of U suggests in the context of this study that oxidative stress is not the only causative factor involved in these behavioral disturbances.…”

“…For example, it has been shown that U is a developmental toxicant with dose-related fetal toxicity (Arfsten et al, 2001). U crosses the blood-brain barrier (Lemercier et al, 2003) and accumulates in the rat brain after chronic exposure (Pellmar et al, 1999a;Paquet et al, 2006), and several experimental studies have found that it has a toxic effect on the behavior of adult rats (Briner and Murray, 2005;Bellès et al, 2005;Houpert et al, 2005;Lestaevel et al, 2005). This behavioral toxicity is expressed by increased locomotor activity (Briner and Muray, 2005;Bellès et al, 2005), significantly decreased spatial working memory capacities , increased anxiety , and shorter paradoxical sleep .…”

“…This behavioral toxicity is expressed by increased locomotor activity (Briner and Muray, 2005;Bellès et al, 2005), significantly decreased spatial working memory capacities , increased anxiety , and shorter paradoxical sleep . In addition to the cerebral cortex (Lestaevel et al, 2013), the hippocampus also seems to be a major target of U-induced neurotoxicity (Pellmar et al, 1999b).…”

Radionuclide exposure in animals and the public health implications

“…Pellmar et al (27) implanted adult Sprague Dawley rats with up to 20 depleted uranium alloy pellets in the gastrocnemius muscle for 18 months. They noted significantly elevated uranium concentrations in the kidneys, liver, spleen, brain, serum, tibia, skull, and urine at most time points.…”