A study Assessing the Genotoxicity in Rats after Chronic Oral Exposure to a Low Dose of Depleted Uranium

Abstract

The aim of this study was to evaluate the potential genotoxicity induced by chronic oral exposure to depleted uranium (DU). Weanling Wistar rats (F(0)), 50/sex/group, were exposed to DU in food at doses of 0, 4, or 40 mg kg(-1)day(-1) for four months. They were subsequently mated, resulting in the birth of F(1) rats. Fifty F(l) weanlings/sex/group were exposed for four months to the same dose levels as their parents. After four months, the uranium content in the tissues, the potential damage to the genetic material, and pathomorphological changes of the testicles were observed in both F(0) and F(1) rats. The genotoxicity of DU was evaluated by the following methods: sperm abnormality assessment, the bone-marrow micronucleus test, and the comet assay. Uranium content in F(1) rats was significantly higher than that in F(0) rats in both the kidney and ovary (p < 0.05). The sperm abnormality rate, marrow cell micronuclei rate, comet tail length, and tailed cell percentage increased in each treatment group in each generation compared with the control group (p < 0.05). When comparing F(1) with F(0) rats, significant differences were detected for most of the indicators, with F(1) rats always exhibiting more damage (p < 0.05). With regard to pathomorphological changes in the testicles, the sperm displayed atypical changes, including thickening of the anachromasis nucleolus, which seemed to be more severe in F(1) rats. Genotoxicity may be induced in rats after chronic oral exposure to a low dose of DU.