Proliferative and migratory responses of astrocytes to in vitro injury

An in vitro "scratch-wound" model was used to evoke and investigate some as troglial responses to mechanical injury. The changes in the morphology, loc omotion, and proliferation of injured astrocytes were analysed under cultur e conditions devoid of blood-derived cells responsible for activating the i nflammatory cascade. The rate of proliferation was determined by immunocyto chemical detection of BrdU-incorporating cells located next to or far from the wound. The motility of individual cells and the mass-advancement of cel l-assemblies were monitored by computer controlled video-microscopy both in injured monolayers and in preparations of single cells or aggregates of as trocytes. The large sets of digitalized data allowed a reliable statistical evaluation of changes in cell positions providing a quantitative approach for studies on dynamics of cell locomotion. The results indicated that cult ivated astrocytes respond to injury (1) with enhanced nestin immunoreactivi ty at the expanding processes, (2) with increased mitotic activity exceedin g the rate caused by the liberation from contact inhibition, but (3) withou t specific, injury-induced activation of cell locomotion. Some advantages a nd drawbacks of "scratch-wound" models of astrocytic responses to mechanica l injury are presented and discussed. (C) 2000 Wiley-Liss, Inc.