The status and organization of astrocytes, oligodendroglia and microglia
in grafts of fetal rat cerebral cortex.
Harvey AR, Kendall CL, Sykova E
Department of Anatomy and Human Biology, The University of Western Australia,
Nedlands, Perth. arharvey@anhb.uwa.edu.au
Immunohistochemical methods were used to study the status and organization
of astrocytes, oligodendroglia and microglia in fetal cerebral cortical
tissue grafted on to the dorsal surface of the midbrain in newborn host
rats. Grafts were examined 1-6 months posttransplantation. All grafts contained
large numbers of hypertrophied, intensely glial fibrillary acidic protein-positive
astrocytes. Microglia were also activated, displaying slightly increased
levels of OX-42 immunoreactivity. The grafts consisted of lobules of gray
matter which were separated by bands of myelinated fibres associated with
large numbers of Rip-positive oligodendroglia. These glial cells had a
relatively normal morphology. The density of astrocytes and microglia was
reduced in these white matter-like regions. In association with chronic
changes in glial reactivity, transplants also expressed increased levels
of chondroitin sulphate proteoglycans (CS-56 antibody). The observed changes
in glial cell phenotype and extracellular matrix in cortical transplants
are likely to affect neuronal physiology and connectivity in a number of
ways, and highlight the importance of studying both glia and neurons in
order to gain a more comprehensive picture of the long-term functional
potential of fetal brain grafts.