Background/Objectives: Betulinic acid is a component of a Chinese traditional herb that upregulates endothelial nitric oxide (NO) synthase (eNOS) and reduces NADPH expression. Increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) after cerebral arterial ischemia is a major cause of neuronal damage. Local venous ischemia can arise that slowly damages surrounding brain tissue during surgical procedures. The present study investigated the effects on infarct size when betulinic acid was administered after inducing two-vein occlusion (2VO) with a slowly developing lesion in rats. Methods: We elicited 2VO in 18 male Wistar rats by the photochemical thrombosis of two adjacent cortical veins combined with KCL-induced cortical spreading depression (CSD). The rats were then randomized into groups (n=9 each) to receive either dimethyl sulfoxide (DMSO) vehicle (control) or betulinic acid (30mg/kg/day; n=9) by daily gavage for seven days, and then infarct volume and 3-nitrotyrosine expression were assessed. Results: Daily administration of betulinic acid for seven days significantly reduced infarct volume from 3.81 ± 0.7 to 1.90 ± 0.3mm³ (p=0.017). Physiological data and regional cerebral blood flow did not significantly differ between the two groups during the study. We found 3-nitrotyrosine expression within the border zone of the infarct area and cleaved caspase-3 only within the lesion at the ipsilateral hemisphere in both groups. However, 3-nitrotyrosine/caspase-3 expression did not significantly differ at any time between the groups. Conclusions: Betulinic acid reduced neuronal damage in a rat model of cerebral venous ischemia.博士（医学）・乙第1460号・令和2年6月30
