Figure 1.

Astrocytes undergo astrogliosis in a pro-inflammatory environment. Astrocytes change their morphology from a non-reactive into a reactive state when exposed to pro-inflammatory cytokines.They undergo hypertrophy and not only change their shape, but also their protein expression; up to this stage, the process is reversible and reactive astrocytes do not overlap their branches. These cells then proliferate and migrate to the lesion site to form the glial scar, where they secrete many factors, such as extracellular matrix (ECM) proteins, cytokines, growth factors (GF), and chondroitin sulfate proteoglycans (CSPG). In this scar-forming stage, astrocytes no longer move, and the process is irreversible.