Dissociative expression of adenoviral-mediated E. coli LacZ gene between ischemic and reperfused rat brains

A replication-defective adenoviral vector containing the E. coli lacZ gene was directly injected into the ischemic or reperfused cerebral cortex of rats. An administration of adenoviral vector showed a slight to moderate expression of the lacZ gene in the cerebral cortex of the middle cerebral artery (MCA) region until 2 days after the MCA occlusion. In contrast, expression of the lacZ gene was not observed, or only minimally so, in the reperfused brain until 2 days after a 90 min of transient MCA occlusion. However, the lacZ expression dramatically increased at 7 days after the reperfusion, then diminished by 21 days. The majority of brain cells that expressed the lacZ gene were neurons and a fraction (5-10%) were astroglial cells. The present study showed that an exogenous gene was transferred and expressed in neural cells of ischemic and reperfused brains in vivo, but the temporal profile of the expression is dissociative.