The dynamic changes of desmin and myosin in rat brain at different periods after stab wound were studied by immunohistochemistry and quantitation methods. The expression of desmin in astrocytes markedly increased and reached its peak on the 7th day and maintained this high level up to 30 days. The zone of reactivity was initially limited to the wound vicinity but spread with time to the entire ipsilateral cortex. The intensity weakened gradually with the increase of distance from the lesion. Myosin was positive mainly in the margin of the wound and partly in the molecular layer of the cortex. The results indicated that the enhancement of desmin expression was closely related to the reactive astrogliosis, whereas the expression of myosin may be a marker of astrocyte hyperplasia. The significance of these responses was discussed.