Effect of Panaxtriol Saponins on synaptophysin and postsynaptic density-95 expression at different periods of cerebral infarction

BACKGROUND： The change in expression of synaptophysin （Syp） and postsynaptic density-95 （PSD-95） alters after cerebral infarction, and the plasticity of synapses contributes greatly to nerve function recovery. Chinese medicinal substances may play an important role in the expression of Syp and PSD-95. OBJECTIVE： To observe the effect of Panaxtriol Saponins （PTS）, an active component in Sanqi tongshu capsules, on the expression of Syp and PSD-95 after cerebral infarction at different time points in rats, so as to examine the cerebral function remodeling mechanism. DESIGN, TIME AND SETTING： A randomized and controlled observation which was performed in Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine from January to March, 2007. MATERIALS： Twenty-six healthy male Sprague Dawley rats were used to establish middle cerebral artery occlusion based on the Longa method. Sanqi tongshu capsules （containing 100 mg PTS per tablet） were provided by the Chengdu Huashen Group and nimodipine tablets （30 mg） by Tianjin Zhongyang Pharmaceutical Co., Ltd. METHODS： Twenty-six rats were randomly divided into an operation group （n = 21 ） and a control group （n = 5）. The operation group underwent the EZ Longa procedure to make the middle cerebral artery occlusion model. After surgery rats were randomly divided into a model group, a PTS group and a nimodipine group, with seven rats in each group. Rats were intragastrically administrated with saline （2 mL/d） in the model group, with Sanqi tongshu capsule （5.4 mg/100 g/d） in the PTS group, and with nimodipine （1.73 mg/100 g/d） in the nimodipine group. Rats in the control group did not undergo model establishment and drug administration. MAIN OUTCOME MEASURES： The expressions of Syp and PSD-95 were measured by immunohistochemical and image analysis at days 3, 7 and 28 after the operation. RESULTS： The expression of Syp and PSD-95 in the operation group was significantly lower than in the control group at days 3, 7, 28 postoperatively （P 〈 0.05）. The expression of Syp and PSD-95 in the PTS group and nimodipine group was significantly higher than in the model group at day 28 postoperatively （P 〈 0.05-0.01）. Additionally, after PTS and nimodipine treatment at different intervals, the expression of Syp and PSD-95 at day 28 postoperatively was significantly higher than those at days 3 and 7 postoperatively, respectively （P 〈 0.01）. CONCLUSION： PTS can promote the expression of Syp and PSD-95, i.e. the remodeling process of synapses, after cerebral infarction at different time points in rats, which contributes to cerebral function remodeling.

Protective effects of Dendrobium nobile Lindl. alkaloids on amyloid beta(25–35)-induced neuronal injury

Dendrobium nobile Lindl.alkaloids（DNLA）,the active ingredients of a traditional Chinese medicine Dendrobium,have been shown to have anti-oxidative effects,anti-inflammatory action,and protective effect on neurons against oxygen-glucose deprivation.However,it is not clear whether DNLA reduces amyloid-beta（Aβ）-induced neuronal injury.In this study,cortical neurons were treated with DNLA at different concentrations（0.025,0.25,and 2.5 mg/L）for 24 hours,followed by administration of Aβ（25-35）（10μM）.Aβ（25-35） treatments increased cell injury as determined by the leakage of lactate dehydrogenase,which was accompanied by chromatin condensation and mitochondrial tumefaction.The damage caused by Aβ（25-35） on these cellular properties was markedly attenuated when cells were pretreated with DNLA.Treatment with Aβ（25-35）down-regulated the expressions of postsynaptic density-95 mRNA and decreased the protein expression of synaptophysin and postsynaptic density-95,all changes were significantly reduced by pretreatment of cells with DNLA.These findings suggest that DNLA reduces the cytotoxicity induced by Aβ（25-35） in rat primary cultured neurons.The protective mechanism that DNLA confers on the synaptic integrity of cultured neurons might be mediated,at least in part,through the upregulation of neurogenesis related proteins synaptophysin and postsynaptic density-95.