Recently, cerebral
ischemic postconditioning (Postcond) has been shown to reduce
infarction volume in
cerebral ischemia/reperfusion (I/R) injury. However, it is unclear if ischemic Postcond offers more extensive neuroprotection than current
therapies. The aim of this study was to investigate the
neuroprotective effects of ischemic Postcond on the neurovascular unit (NVU). A
middle cerebral artery occlusion rat model was used;
cerebral infarct volumes, neurologic scores, and transmission electron microscopy were evaluated 24 h after reperfusion. We used
Evans blue extravasation, immunohistochemistry, and Western blot analyses to evaluate the integrity of the blood brain barrier (BBB) and the distribution and expression of the tight junction (TJ)-associated
proteins of
claudin-5 and
occludin in brain microvessel endothelium. The Postcond group showed significantly reduced
infarct volumes and decreased neurologic impairment scores compared to the I/R group. Also,
injuries to the cerebral microvascular endothelial cells, astrocytes, and neurons were minimized in the Postcond group. The permeability of the BBB increased in both the I/R and Postcond groups, but the Postcond group showed a significant decrease in permeability than the I/R group. Expression of both
claudin-5 and
occludin were higher in the Postcond groups compared to the I/R group, but expression of both
proteins decreased in the I/R and Postcond groups compared to the
sham group. The results of our study suggest that ischemic Postcond is an effective way to reduce injury to neurons, astrocytes, and endothelial cells, to increase
protein expressions of TJ-associated
proteins, and to improve BBB intergrity affected by focal I/R. Ischemic Postcond could protect the NVU from I/R injury.