Nerve cell loss in the progressive encephalopathy induced by aluminum powder. A morphologic and semiquantitative study of the Purkinje cells

The injection of aluminum powder into the cerebrospinal fluid induces a slowly progressing encephalomyelopathy with cerebellar atrophy. We have studied the changes in the cerebellar cortex in order to establish whether Purkinje cell loss takes place. The rabbits were killed by perfusion with paraformaldehyde and glutaraldehyde at intervals from 3 to 85 days after injection of aluminum. Changes were observed in all animals killed between 12 and 85 days after the injection. Neurofibrillary degeneration with 10 nm neurofilaments was observed in the perikaryon of Purkinje cells. The neurofibrillary tangles extended into the proximal part of the dendrites and of the axons. A time-related deterioration of the Purkinje cells was observed. These cells appeared atrophic with eccentric and shrunken nuclei and with dark cytoplasm. By electron microscopy debris of Purkinje cell perikarya, dendrites and axons were found. The semiquantitative analysis revealed a time-related loss of Purkinje cells. Atrophy of the molecular and granule cell layers was observed. A marked proliferation of glial cells contrasted with the severe neuronal losses. Such findings may be relevant to several human diseases in which the central nervous system is exposed to aluminum over long periods of time.