Protective effect of Panax quinquefolium 20(S)-protopanaxadiol saponins, isolated from Pana quinquefolium, on permanent focal cerebral ischemic injury in rats

Abstract

Oxidative stress is significant in the pathogenesis of cerebral ischemia. Panax quinquefolium 20(S)-protopanaxadiol saponins (PQDS) have been demonstrated to exhibit a variety of biological effects in the cardiovascular system as a result of their antioxidant properties. However, little is known regarding the effect of PQDS on cerebral ischemia. The purpose of this study was to investigate whether PQDS exhibited protective effects against cerebral ischemia. A model of cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Adult male rats were randomly divided into five groups: Sham, MCAO and PQDS treatment groups at doses of 12.5, 25.0 and 50.0 mg/kg. The effects of PQDS on neurological deficits, cerebral infarct area, brain water content, and the malondialdehyde (MDA) and Ca2+ levels and Na+-K+-ATPase and superoxide dismutase (SOD) activities in the brain tissue were analyzed, and the nitric oxide (NO) content and nitric oxide synthase (NOS) activity in the serum were evaluated. Moreover, the expression of Bcl-2 was analyzed using western blotting. Pretreatment with PQDS (25.0 and 50.0 mg/kg) significantly reduced the neurological deficit score, decreased the infarcted area and decreased the brain water content from 83.09 to 80.27% (P<0.05). In addition, PQDS pretreatment decreased the NOS activity and the NO levels in the serum compared with those in the MCAO group. Furthermore, pretreatment with PQDS (25.0 and 50.0 mg/kg) significantly increased the activities of SOD and Na+-K+-ATPase and decreased the levels of Ca2+ and MDA in the brain tissue (P<0.05) compared with those in the MCAO group. Pretreatment with PQDS (25.0 and 50.0 mg/kg) also increased the protein expression level of Bcl-2 compared with that in the MCAO group. The histopathological results demonstrated the protective effect of PQDS on ischemic injury. The results indicated that PQDS has protective effects against ischemic injury in rats. The mechanism may be associated with the inhibition of oxidative stress and apoptosis.