Figure 3

EM details of damage evolution and glial scar formation. Micrographs at different time points after stroke. At 48hr the transition zone (TZ) (A) is observed. Black arrows point to synaptic contacts and black stars indicate cellular ghosts (B). (C) shows a detail of infiltrating neutrophils. At 1wk macrophages (white arrows) appear in the necrotic neuropil (D) and astrocytes (black arrows) delineate the lesion border (E). In some cases mitoses of astrocytes are observed (F). At 2wk after stroke, large macrophages (black arrows) and infiltrated neurotrophils (white arrows) occupy the majority of the lesion volume (G). Hypertrophic astrocytes with plenty of intermediate filaments (black arrows) display lining the ischemic boundary (H-I). Black arrowheads indicate rough endoplasmic reticulum cisternae and white arrowheads point to small dictiosomes. At 4wk after stroke, an imbricate layer of hypertrophied astrocytes composes the boundary of the ischemic zone (J-K). At higher magnification these astrocytes appeared attached by tight junction (black arrows). L-M show a detail of astrocytes associated to collagen fibers, forming a base membrane (BV:blood vessel; As:astrocyte).