We determined the role of endogenous
hydrogen sulfide (H2S) in cerebral vasodilation/
hyperemia and early BBB disruption following
ischemic stroke. A cranial window was prepared over the left frontal, parietal and temporal cortex in mice. Transient focal
cerebral Ischemia was induced by directly ligating the middle cerebral artery (MCA) for two hours. Regional vascular response and cerebral blood flow (CBF) during
ischemia and reperfusion were measured in real time. Early BBB disruption was assessed by
Evans Blue (EB) and
sodium fluorescein (Na-F) extravasation at 3 hours of reperfusion. Topical treatment with DL-
propargylglycine (PAG, an inhibitor for
cystathionine γ-
lyase (CSE)) and
aspartate (ASP, inhibitor for
cysteine aminotransferase/3-mercaptopyruvate
sulfurtransferase (CAT/3-MST)), but not O-(Carboxymethyl)
hydroxylamine hemihydrochloride (CHH, an inhibitor for
cystathionine β-synthase (CBS)), abolished postischemic cerebral vasodilation/
hyperemia and prevented EB and Na-F extravasation. CSE knockout (CSE-/-) reduced postischemic cerebral vasodilation/
hyperemia but only inhibited Na-F extravasation. An upregulated CBS was found in cerebral cortex of CSE-/- mice. Topical treatment with CHH didn't further alter postischemic cerebral vasodilation/
hyperemia, but prevented EB extravasation in CSE-/- mice. In addition,
L-cysteine-induced
hydrogen sulfide (H2S) production similarly increased in ischemic side cerebral cortex of control and CSE-/- mice. Our findings suggest that endogenous production of H2S by CSE and CAT/3-MST during reperfusion may be involved in postischemic cerebral vasodilation/
hyperemia and play an important role in early BBB disruption following transient focal
cerebral ischemia.