The neurotoxic effect of iron on pyramidal cell number in rat hippocampus: a stereological study

There have been numerous studies of neuronal hyperactivity and oxidative stress induced by iron. Moreover, it has been found that iron levels in the brain are markedly increased in some neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). We attempted to identify the toxic effect of iron on the hippocampus, a region of the brain known to be involved in learning and memory processes and which lends itself to stereological analysis. Rats were given iron chloride (FeCl35H2O), 200 mM in 2.5 μl) intracortically and were killed 10 days later. The total number of neurons in the hippocampus of control and iron-treated rats was counted with an optical fractionator. Iron administration caused a significant decrease in the total number of pyramidal neurons in the left (31.6% decrease) and right (32.2% decrease) hippocampi (p<0.001). The findings suggest that excess iron contributes to pyramidal cell death in the rat hippocampus.