Functional impairment after
brain ischemia results in part from loss of neuronal spines and dendrites, independent of neuronal death.
Cofilin-actin rods are covalently linked aggregates of cofilin-1 and actin that form in neuronal processes (neurites) under conditions of
ATP depletion and oxidative stress, and which cause neurite degeneration if not disassembled.
ATP depletion and oxidative stress occur with differing severity, duration, and time course in different ischemic conditions. Here we evaluated four mouse models of
brain ischemia to define the conditions that drive formation of
cofilin-actin rods. Three of the models provide early reperfusion: transient
middle cerebral artery occlusion (MCAo), transient bilateral common carotid artery occlusion (CCAo), and
cardiac arrest /
cardiopulmonary resuscitation (CA/
CPR). Early reperfusion restores
ATP generating capacity, but also induces oxidative stress. The fourth model, photothrombotic cortical
infarction, does not provide reperfusion.
Cofilin-actin rods were formed in each of these models, but with differing patterns. Where acute reperfusion occurred, rod formation was maximal within 4 hours after reperfusion. Where
infarction occurred, rods continued to form for at least 24 hours after ischemic onset, and extended into the adjacent non-ischemic tissue. Interventions that limit
cofilin-actin rod formation may help to preserve integrity of neuronal processes in permanent
ischemia.