Figure 1.

An in vitro model to study the effects of TBI in the presence of Aβ pathology. (A) Schematic outline of the experimental set-up. Differentiated cell cultures (astrocytes (green), neurons (gold) and oligodendrocytes (cyan); represented according to observation) were exposed to 0.1 µM Aβ₄₂ protofibrils for 24 h. The cells were then rinsed extensively before being subjected to experimental TBI, a mechanically induced scratch injury performed with a scalpel. Subsequently, the cells were cultured for three additional days. (A′) Depiction of the four groups used in this study: untreated (control), scratch injured (TBI), exposed to Aβ₄₂ protofibrils (PF) and the combination of both (TBI + PF). (B) Representative image of the co-culture exposed to Aβ₄₂ protofibrils and stained for astrocytes (GFAP) and Aβ. (B′) A higher magnification of the area outlined by the square in (B), showing a close-up of the Aβ deposits (some of different sizes are pointed out by the arrow heads). Orthogonal projections were made along the lines depicted in the main image and show the Aβ inclusion surrounded by GFAP. (C) Representative images of astrocytes (GFAP), neurons (βIII tubulin) and oligodendrocytes (CNPase). The scalpel cuts left noticeable injuries, which are outlined by the dashed lines. The three cell types react differently to the injury. Astrocytes extend towards and along the cut and the arrow head draws attention to an astrocyte growing into the area of laceration. Neurons also grow towards and along, but do not breach, the site of injury. Oligodendrocytes avert the area of the cut, unless in its direct vicinity, but were not observed to grow across the injury site. (C′) Magnification of the areas outlined in (C). Scale bars 20 µm (B,B′,C′) and 50 µm (C).