Summary
Stroke elicits a progressive vascular dysfunction, which contributes to the evolution
of brain injury. Thrombolysis with tissue plasminogen activator (tPA) promotes adverse
vascular events that limit the therapeutic window of stroke to three hours. Proteasome
inhibitors reduce vascular thrombotic and inflammatory events, and consequently protect
vascular function. The present study evaluated the neuroprotective effect of bortezomib,a
potent and selective inhibitor of the proteasome, alone and in combination with delayed
thrombolytic therapy on a rat model of embolic focal cerebral ischemia. Treatment
with bortezomib reduces adverse cerebrovascular events including secondary thrombosis,inflammatory
responses,and blood brain barrier (BBB) disruption, and hence reduces infarct volume
and neurological functional deficit when administrated within 4 h after stroke onset.
Combination of bortezomib and tPA extends the thrombolytic window for stroke to6 h,
which is associated with the improvement of vascular patency and integrity. Real time
RT-PCR of endothelial cells isolated by laser-capture microdissection from brain tissue
and Western blot analysis showed that bortezomib upregulates endothelial nitric oxide
synthase (eNOS) expression and blocks NF-κB activation. These results demonstrate
that bortezomib promotes eNOS dependent vascular protection, and reduces NF-κB dependent
vascular disruption, all of which may contribute to neuroprotection after stroke.
Keywords
Animal models - adhesion molecules - plasminogen activators