Proliferative and migratory responses of astrocytes to in vitro injury

Zs. Környei 1,  A. Czirók 2, T. Vicsek 2, and E. Madarász 1

1 Institute of Experimental Medicine, Budapest, Hungary
2 Department of Biological Physics, Eötvös University, Budapest, Hungary

An in vitro "scratch-wound" model was used to evoke and investigate some astroglial responses to mechanical injury. The changes in the morphology, locomotion, and proliferation of injured astrocytes were analysed under culture conditions devoid of blood-derived cells responsible for activating the inflammatory cascade. The rate of proliferation was determined by immunocytochemical detection of BrdU-incorporating cells located next to or far from the wound. The motility of individual cells and the mass-advancement of cell-assemblies were monitored by computer controlled video-microscopy both in injured monolayers and in preparations of single cells or aggregates of astrocytes. 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 cultivated astrocytes respond to injury (1) with enhanced nestin immunoreactivity at the expanding processes, (2) with increased mitotic activity exceeding the rate caused by the liberation from contact inhibition, but (3) without specific, injury-induced activation of cell locomotion. Some advantages and drawbacks of "scratch-wound" models of astrocytic responses to mechanical injury are presented and discussed. Copyright 2000 Wiley-Liss, Inc.

Published in J Neurosci Res 2000 Aug 15;61(4):421-9

Supplemental movies

Rat embrionic type-I astroglia culture: 10 Mbyte mpeg stream.
Objective: 20X (Field of view: 210um X 160um). Duration of recording: 3 days. Number of frames: 937 (5 min/frame).
Note the cessation of locomotory activity at confluence.

Migration from aggregates
: 9 Mbyte mpeg stream.
Objective: 10X (Field of view: 420um X 320um). Duration of recording: 3 days. Number of frames: 824 (5 min/frame).

Note the rather coordinated motion of the cells despite the high local cell density.

Cell invasion after mechanical injury of the monolayer: 8 Mbyte mpeg stream.
Objective: 10X (Field of view: 420um X 320um). Duration of recording: 2 days. Number of frames: 560 (5 min/frame).
Note the similar behavior to that seen for the expanding aggregates. The bright localised "flashes" are cell divisions.