Neuroprotective effect of morroniside on focal cerebral ischemia in rats

Cornus officinalis Sieb. et Zucc., known as Shan-zhu-yu in Chinese, has been used to treat cerebrovascular disease and diabetes in Traditional Chinese Medicine for a long time and morroniside is the main component of Shan-zhu-yu. In this study, we examined whether morroniside could protect ischemia/reperfusion-induced brain injury by minimizing oxidative stress and anti-apoptosis. Morroniside was intragastrically administered to rats in doses of 30, 90 and 270mg/kg/day, starting 3h after the onset of middle cerebral artery occlusion. The behavioral test was performed by using the Zea-Longa scores, Prehensile Traction score and Ludmila Belayer score. Rats were sacrificed 3 days after ischemia occurred. The infarction volume of brain was assessed in the brain slices stained with 2,3,5-triphenyl tetrazolium chloride. Cortex tissues were also used for determination of malondialdehyde levels, glutathione levels and superoxide dismutase. The treatment with morroniside significantly improved Zea-Longa scores and Prehensile Traction score at the doses of 30, 90 and 270mg/kg, increased Ludmila Belayer score and reduced the infarction volume at the doses of 90 and 270mg/kg. Morroniside (30, 90 and 270mg/kg) treatment significantly decreased the level of malondialdehyde and caspase-3 activity by colorimetric analysis in ischemic cortex tissues. Morroniside (270mg/kg) treatment significantly increased the content of glutathione, enhanced the activity of superoxide dismutase, but decreased the caspase-3 expression by Western-blot analysis in ischemic cortex tissues. These findings demonstrated that morroniside could notably protect the brain from damage induced by focal cerebral ischemia which might be related to morroniside antioxidant and anti-apoptotic properties in the brain.