Total Saponins of Panax notoginseng Activate Akt/mTOR Pathway and Exhibit Neuroprotection in vitro and in vivo against Ischemic Damage / 中国结合医学杂志

OBJECTIVE@#To reveal the neuroprotective effect and the underlying mechanisms of a mixture of the main components of Panax notoginseng saponins (TSPN) on cerebral ischemia-reperfusion injury and oxygen-glucose deprivation/reoxygenation (OGD/R) of cultured cortical neurons.@*METHODS@#The neuroprotective effect of TSPN was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometry and live/dead cell assays. The morphology of dendrites was detected by immunofluorescence. Middle cerebral artery occlusion (MCAO) was developed in rats as a model of cerebral ischemia-reperfusion. The neuroprotective effect of TSPN was evaluated by neurological scoring, tail suspension test, 2,3,5-triphenyltetrazolium chloride (TTC) and Nissl stainings. Western blot analysis, immunohistochemistry and immunofluorescence were used to measure the changes in the Akt/mammalian target of rapamycin (mTOR) signaling pathway.@*RESULTS@#MTT showed that TSPN (50, 25 and 12.5 µ g/mL) protected cortical neurons after OGD/R treatment (P<0.01 or P<0.05). Flow cytometry and live/dead cell assays indicated that 25 µ g/mL TSPN decreased neuronal apoptosis (P<0.05), and immunofluorescence showed that 25 µ g/mL TSPN restored the dendritic morphology of damaged neurons (P<0.05). Moreover, 12.5 µ g/mL TSPN downregulated the expression of Beclin-1, Cleaved-caspase 3 and LC3B-II/LC3B-I, and upregulated the levels of phosphorylated (p)-Akt and p-mTOR (P<0.01 or P<0.05). In the MCAO model, 50 µ g/mL TSPN improved defective neurological behavior and reduced infarct volume (P<0.05). Moreover, the expression of Beclin-1 and LC3B in cerebral ischemic penumbra was downregulated after 50 µ g/mL TSPN treatment, whereas the p-mTOR level was upregulated (P<0.05 or P<0.01).@*CONCLUSION@#TSPN promoted neuronal survival and protected dendrite integrity after OGD/R and had a potential therapeutic effect by alleviating neurological deficits and reversing neuronal loss. TSPN promoted p-mTOR and inhibited Beclin-1 to alleviate ischemic damage, which may be the mechanism that underlies the neuroprotective activity of TSPN.

Effects of ginsenoside RH2 on neovascularization of rats with middle cere-bral artery occlusion / 中国病理生理杂志

AIM:To investigate the effects of ginsenoside RH 2(GS-RH2 )on neovascularization of rats with middle cerebral artery occlusion(MCAO)and its potential mechanisms.METHODS:SPF Sprague-Dawley rats were ran-domly divided into sham operation(sham)group,MCAO model(MCAO)group and GS-RH2 group,with 18 rats in each group.After surgery,the general condition and neurological function score of the rats were assessed.At the 1st day,3rd day and 7th day after intervention,the microvessel density(MVD),the content of malondialdehyde(MDA)and the activ-ity of superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)were examined.The protein expression of kelch-like ECH-associated protein 1(Keap1),nuclear factor E2-related factor 2(Nrf2)and heme oxygenase-1(HO-1)was de-termined by Western blot.RESULTS:Compared with sham group ,the rats in MCAO group showed significant neurobe-havioral obstacles and ischemic brain infarction with higher neurological function score ,while treatment with GS-RH2 sig-nificantly improved behavioral impairment and reduced the infarction volume with lower neurological function score.The MVD score in GS-RH2 group was increased as the animal survival time prolonged ,while the MVD score in MCAO group was decreased.After intervention for 7 d,the MVD score in GS-RH2 group was significantly higher than that in MCAO group(P<0.05).Compared with sham group,the content of MDA was increased and the activities of SOD and GSH-Px were decreased in MCAO group at each time point.After intervention for 7 d,the MDA content was decreased and the SOD and GSH-Px activities were increased in GS-RH2 group compared with MCAO group.After intervention for 7 d,the protein expression of Nrf2 and HO-1 was increased,while the protein expression of Keap1 was decreased in GS-RH2 group com-pared with MCAO group(P<0.05).CONCLUSION:Ginsenoside RH2 promotes neovascularization of MCAO model rats.The mechanism may be related to the activation of Keap 1/Nrf2 signaling pathway ,promotion of the antioxidant enzyme activity and inhibition of oxidative stress.