Anfibatide Preserves Blood-Brain Barrier Integrity by Inhibiting TLR4/RhoA/ROCK Pathway After Cerebral Ischemia/Reperfusion Injury in Rat.

Abstract

The disruption of the blood-brain barrier (BBB) and the consequent brain edema are major contributors to the pathogenesis of cerebral ischemia/reperfusion injury. RhoA is generally thought to play a crucial role in the process of BBB disruption and participate in the signaling pathways emanating from TLR4. However, it remains unverified the regulatory role of TLR4 in the RhoA/ROCK pathway in cerebral I/R injury and its effects on the BBB as well. The present study probes into the protective effect of ANF on the BBB after cerebral I/R injury and the possible mechanisms. Focal cerebral ischemia was induced by 120min of transient middle cerebral artery occlusion (MCAO). ANF (1, 2, 4μg/kg) was achieved by intravenous injection after 120min of MCAO followed by 1, 24, 48, and 72h reperfusion. Evans blue extravasation, brain water content, RhoA activity, and the expressions of TLR4, ROCK1/2, p-MLC2, MMP-2/9, ZO-1, occludin, and claudin-5 protein in rat brain were evaluated 72h after reperfusion. ANF could significantly reduce the Evans blue extravasation and water content in the ipsilateral hemisphere and obviously increase the occludin, claudin-5, and ZO-1 expression after cerebral I/R injury. Furthermore, cerebral I/R injury induced apparently increased expression of TLR4, RhoA-GTP, ROCK1/2, p-MLC2, and MMMP-2/9, which, however, could be remarkably alleviated by ANF intervention. Taken together, the TLR4/RhoA/ROCK signaling pathway is implicated in BBB breakdown after cerebral I/R injury, and ANF preserves BBB integrity, probably via inhibiting the TLR4/RhoA/ROCK signaling pathway.