Protective Effect of Cyclosporin A on White Matter Changes in the Rat Brain After Chronic Cerebral Hypoperfusion

Background and Purpose Activation of glial cells and rarefaction of the white matter have been reported in rat brain after bilateral permanent occlusion of the common carotid arteries. Using this model, we investigated the effects of the immunosuppressant cyclosporin A on the activation of glial cells and the white matter rarefaction. Methods Both common carotid arteries were ligated bilaterally in 40 male Wistar rats. Twenty-two of these rats received an intraperitoneal injection of cyclosporin A, and the remaining 18 received a vehicle-solution injection. Microglia/macrophages were investigated with immunohistochemistry for the major histocompatibility complex class I and II antigens as well as for leukocyte common antigen. Astroglia were examined with glial fibrillary acidic protein as a marker. Activation of glial cells and white matter rarefaction were then investigated from 7 to 30 days after the ligation. Results In vehicle-treated animals, there was a persistent and extensive activation of both mi...