KDR and brain ischemia: Brain-Derived Cystathionine β-Synthase-Generated H&lt;sub&gt;2&lt;/sub&gt;S Attenuates Cerebral Ischemia-Reperfusion Injury via VEGFR&lt;sub&gt;2&lt;/sub&gt;-Mediated Angiogenesis in MCAO/R Rats.