Bull Mem Acad R Med Belg. 2003;158(7-9):329-33; discussion 333-4
Faculte de Medecine, Universite des Emirats Arabes Unis, BP 17666, Al Ain, Emirats Arabes Unis.
Glia form a cellular network consisting mainly of astrocytes that nourish the neurons, oligodendrocytes that form myelin, and microglia that ensure the immunological defence of the nervous system.
Experimental allergic encephalomyelitis is an animal model of multiple sclerosis, characterised by cellular infiltrates and demyelinisation in the central nervous system.
It can be induced in susceptible rats (DA) by inoculation of foreign protein.
Other, non-susceptible rats (AO) have infiltrates that disappear without functional signs of disease.
We have found microglia and astrocytes in infiltrates 10 days after inoculation.
At 14 days they are even more marked in the DA, but astrocytosis is less in the AO.
Microglia have disappeared at 14 days in the DA, but persist in the AO.
We suggest that the infiltrates are dispersed by microglial activity that persists in the AO and prevents astrocytosis.
In the DA the loss of microglia allows gliosis to occur, with demyelination due to lesions of oligodendrocytes, and clinical signs.
We have also studied astrocytes and microglia in the cerebral cortex of schizophrenics and control non-schizophrenics.
The number of astrocytes does not vary between patients and controls, but microglia are more numerous in the patients.
We conclude that there is a cortical microgliosis in schizophrenia that may be a response to an earlier lesion, perhaps protecting neighbouring neurons.