Oxidative injury in the brain of mice caused by lanthanid.

The organ toxicity of lanthanides (Ln) on organisms had been recognized, but very little is known about the oxidative injury of brain caused by Ln. In order to study the mechanisms underlying the effects of Ln on the brain, ICR mice were injected with a single 20 mg/kg body weight dose of LaCl(3), CeCl(3), and NdCl(3) into the abdominal cavity daily for 14 days. We then examined the coefficient of the brain, the brain pathological changes and oxidative stress-mediated responses, and the accumulation of Ln and levels of neurochemicals in the brain. The results showed that CeCl(3) and NdCl(3) could induce some neurons to turn inflammatory cells and slight edema but did not observe the brain pathological changes from LaCl(3)-treated group. The concentrations of La, Ce, and Nd in the brain were significantly different and ranked in the order of Ce, Nd, and La. The injury of the brain and oxidative stress occurred as Ln appeared to trigger a cascade of reactions such as lipid peroxidation, the decreases of the total antioxidation capacity and activities of antioxidative enzymes, the excessive release of nitric oxide, the increase of glutamic acid, and the downregulated level of acetylcholinesterase activities. Furthermore, both Ce(3+) and Nd(3+) exhibited higher oxidative stress and toxicity on brain than La(3+), and Ce(3+) caused more severe brain injuries and oxidative stress than Nd(3+), implying that the differences in the brain injuries caused by Ln might be related to the number of 4f electrons of Ln.