Intranuclear aluminum accumulation in chronic animals with experimental neurofibrillary changes.

Young New Zealand white rabbits (1.5 kg body weight) subjected to daily subcutaneous injection of aluminum tartrate (7.7 mg/kg body weight) developed neurofibrillary tangles (NFTs) in specific areas of the central nervous system. The NFTs were initially observed in the spinal cord and brain stem. The hippocampus was the last region to show NFTs. Animals neither died nor showed any neurologic signs. Their growth pattern during and following the aluminum injection was comparable to that of controls. Energy-dispersive X-ray spectrometry detected aluminum within the nucleus of a high percentage of NFT-bearing neurons in the spinal cord and hippocampus. Aluminum was not detected in NFT-free neurons. These findings suggest the association of intranuclear aluminum with NFTs induced experimentally in the chronic animals.