Betulinic acid protects against cerebral ischemia–reperfusion injury in mice by reducing oxidative and nitrosative stress

Increased production of reactive oxygen and nitrogen species following cerebral ischemia-reperfusion is a major cause for neuronal injury. In hypercholesterolemic apolipoprotein E knockout (ApoE-KO) mice, 2h of middle cerebral artery (MCA) occlusion followed by 22h of reperfusion led to an enhanced expression of NADPH oxidase subunits (NOX2, NOX4 and p22phox) and isoforms of nitric oxide synthase (neuronal nNOS and inducible iNOS) in the ischemic hemisphere compared with the non-ischemic contralateral hemisphere. This was associated with elevated levels of 3-nitrotyrosine, an indicator of peroxynitrite-mediated oxidative protein modification. Pre-treatment with betulinic acid (50mg/kg/day f…