Disruption of the blood-cerebrospinal fluid barrier by transient cerebral ischemia.

The influence of transient cerebral ischemia on blood-brain and blood-cerebrospinal fluid (CSF) barrier permeability was studied sequentially by magnetic resonance imaging (MRI) contrast enhancement using gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) in rats. The unilateral internal carotid and middle cerebral arteries were transiently occluded by inserting a nylon thread into the carotid artery and removing it following a variable interval of 5 to 60 min. Contrast enhancement of the lateral ventricle on the affected side was seen in the enhanced T1-weighted image at the early stage of reperfusion 6 h after the start of ischemia in most of the rats subjected to 30- and 60-min ischemia, and in 3 of 6 rats in the 15-min ischemia group. Autoradiograms of Gd-[14C]DTPA in rats subjected to 60-min ischemia demonstrated that the tracer strongly accumulated in the choroid plexus, the wall of the lateral ventricle and its surrounding brain tissue. On the other hand, parenchymal enhancement of the striatum was seen only in the 60-min ischemia group and appeared later on Day 1 or Day 7. These results indicate that ventricular enhancement on MRI in this model is caused by disruption of the blood-CSF barrier at the choroid plexus of the lateral ventricle. This is the first reported study to demonstrate blood-CSF barrier disruption by transient ischemia.