Shikonin protects mouse brain against cerebral ischemia/reperfusion injury through its antioxidant activity

The aim of our study was to investigate the neuroprotective properties of shikonin, a naphthoquinone pigment isolated from the roots of the traditional Chinese herb Lithospermum erythrorhizon. In the present study, mice were divided randomly into sham, model, shikonin and edaravone-treated groups. Shikonin (50, 25, and 12.5 mg/kg, i.g.) or maize oil was administered three times before ischemia and once at 2 h after the onset of ischemia. Mice were anesthetized with chloral hydrate and subjected to middle cerebral artery 2 h of occlusion and then 22 h of reperfusion. Different antioxidant assays were employed in order to evaluate the antioxidant activities of shikonin in vitro. Neurological deficit, infarct size, histopathology changes and oxidative stress markers were evaluated after 22 h of reperfusion. In comparison with the model group, treatment with shikonin significantly decreased neurological deficit scores, infarct size, the levels of malondialdehyde(MDA), carbonyl and reactive oxygen species, and attenuated neuronal damage, up-regulated superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio. Taken together, these results suggested that the neuroprotective effects of shikonin against cerebral ischemia/reperfusion injury may be attributed to its antioxidant effects.