Danhong injection (DHI), a Chinese Materia Medica standardized product extracted from Radix Salviae miltiorrhizae and Flos Carthami tinctorii, is widely used in China for treating acute isch-emic stroke. In the present study, we explored the neuroprotective efifcacy of DHI in a rat model of temporary middle cerebral artery occlusion, and evaluated the potential mechanisms under-lying its effects. Pretreatment with DHI (0.9 and 1.8 mL/kg) resulted in a signiifcantly smaller infarct volume and better neurological scores than pretreatment with saline. Furthermore, DHI significantly reduced the permeability of the blood-brain barrier, increased occludin protein expression and decreased neutrophil inifltration, as well as profoundly suppressing the upreg-ulation of matrix metallopeptidase-9 expression seen in rats that had received vehicle. Matrix metallopeptidase-2 expression was not affected by ischemia or DHI. Moreover, DHI (1.8 mL/kg) administered 3 hours after the onset of ischemia also improved neurological scores and reduced infarct size. Our results indicate that the neuroprotective efifcacy of DHI in a rat model of ce-rebral ischemia-reperfusion injury is mediated by a protective effect on the blood-brain barrier and the reversal of neutrophil inifltration.

Amyloid β-peptide, a major component of senile plaques in Alzheimer’s disease, has been impli-cated in neuronal cel death and cognitive impairment. Recently, studies have shown that the pathogenesis of cerebral ischemia is closely linked with Alzheimer’s disease. In this study, a rat model of global cerebral ischemia-reperfusion injury was established via occlusion of four arteries;meanwhile, fibril ar amyloid β-peptide was injected into the rat lateral ventricle. The Morris water maze test and histological staining revealed that administration of amyloid β-peptide could further aggravate impairments to learning and memory and neuronal cel death in the hippocampus of rats subjected to cerebral ischemia-reperfusion injury. Western blot showed that phosphorylation of tau protein and the activity of glycogen synthase kinase 3β were significantly stronger in cerebral is-chemia-reperfusion injury rats subjected to amyloidβ-peptide administration than those undergoing cerebral ischemia-reperfusion or amyloidβ-peptide administration alone. Conversely, the activity of protein phosphatase 2A was remarkably reduced in rats with cerebral ischemia-reperfusion injury fol owing amyloidβ-peptide administration. These findings suggest that amyloidβ-peptide can po-tentiate tau phosphorylation induced by cerebral ischemia-reperfusion and thereby aggravate cog-nitive impairment.