Neuroglial activity in the focus of ischemic stroke

Abstract

Objective: To study the dynamics of morphochemical modifications in glial cells of rat neocortex under the conditions of experimental stroke, induced by means of constant occlusion of the middle brain artery.Methods: We studied the immunolocalisation of glial cell-derived neurotrophic factor (GDNF), glial fibrillary acidic protein (GFAP), Iba-1 and S-100 in the rat parietal cortex during the constant occlusion of middle brain artery.Results: Astrocytes, expressing GFAP and S-100, are found in the penumbra area and define its borders. In the later stages of stroke, the density of astrocytes increases on the border of the stroke focus and decreases around penumbra, which leads to immunoreactive perifocal zone boarders shifting and its significant narrowing. The reversion of immunoreactivity during the early and late stages of stroke was observed. The reversion was defined by decrease in S-100-expression in astrocytes and expression presence in pyramidal neurons on the 1-3 day of ischemia in the stroke focus. The reverse tendency toward localization changes of GDNF from neurons to astrocytes was detected in penumbra on 8-21 day. Iba-1-reactive microglia at the stroke’s core shows the sings of activated macrophages - increase in the cells’ size, reduction in quantity and branching. Iba-1-reactive microglia concentrates in the stroke focus, reaching its highest point on the 8 day and corresponds to decreasing spatial density of astrocytes in the penumbra area.Conclusions. Specificity of the morphochemical alteration of glial cells closely interacts with the condition of neurons in the stroke focus, points to the penumbra borders and connected with the balance of various protective and neurodestructive processes.