Effects of total saponins of Panax notoginseng on immature neuroblasts in the adult olfactory bulb following global cerebral ischemia/reperfusion

The main active components extracted from Panax notoginseng are total saponins. They have been shown to inhibit platelet aggregation, increase cerebral blood flow, improve neurological behavior, decrease infarct volume and promote proliferation and differentiation of neural stem cells in the hippocampus and lateral ventricles. However, there is a lack of studies on whether total saponins of Panax notoginsertg have potential benefits on immature neuroblasts in the olfactory bulb following ischemia and reperfusion. This study established a rat model of global cerebral ischemia and reperfusion using four-vessel occlusion. Rats were administered total sa- ponins of Panax notoginseng at 75 mg/kg intraperitoneally 30 minutes after ischemia then once a day, for either 7 or 14 days. Total saponins of Panax notoginseng enhanced the number of dou- blecortin （DCX）＋ neural progenitor ceils and increased co-localization of DCX with neuronal nuclei and phosphorylated cAMP response element-binding/DCX＋ neural progenitor cells in the olfactory bulb at 7 and 14 days post ischemia. These findings indicate that following global brain ischemia/reperfusion, total saponins of Panax notoginseng promote differentiation of DCX＋ cells expressing immature neuroblasts in the olfactory bulb and the underlying mechanism is related to the activation of the signaling pathway of cyclic adenosine monophosphate response element binding protein.

Total Saponins of Panax notoginseng Activate Akt/mTOR Pathway and Exhibit Neuroprotection in vitro and in vivo against Ischemic Damage

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 oxygenglucose 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 12.5μg/m L)protected cortical neurons after OGD/R treatment(P<0.01 or P<0.05).Flow cytometry and live/dead cell assays indicated that 25μg/m L TSPN decreased neuronal apoptosis(P<0.05),and immunofluorescence showed that 25μg/m L TSPN restored the dendritic morphology of damaged neurons(P<0.05).Moreover,12.5μg/m L TSPN downregulated the expression of Beclin-1,Cleaved-caspase 3 and LC3 B-Ⅱ/LC3 B-Ⅰ,and upregulated the levels of phosphorylated(p)-Akt and p-mTOR(P<0.01 or P<0.05).In the MCAO model,50μg/m L TSPN improved defective neurological behavior and reduced infarct volume(P<0.05).Moreover,the expression of Beclin-1 and LC3 B in cerebral ischemic penumbra was downregulated after 50μg/m L TSPN treatment,whereas the p-mTOR level was upregulated(P<0.05 or P<0.01).Conclusions: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.

Atherosclerosis lesion is accelerated by persistent systemic inflammation but attenuated by saponins from Panax Notoginseng in rabbits

Objective： To explore the roles of persistent systemic inflammation in atherosclerosis and the effects of saponins of Panax Notoginseng （PNS） on this process in rabbits. Methods： Thirty rabbits were divided randomly and equally into 6 groups, i.e., control, high-fat diet, inflammation, aspirin, PNS and simple-inflammation group. All the animals except that in control group and simple-inflammation group were fed with high-fat diet for 8 weeks. Based on that, rabbits in inflammation, aspirin and PNS groups were treated with zymosan injection （10 mg/kg, i.p.）. Normal saline was given to rabbits in control group. Besides zymosan injection, animals in aspirin and PNS group were administrated with aspirin （12 mg/kg, i.g.） and PNS （120 mg/kg, i.g.） respectively. The animals in simple-inflammation group were treated with zymosan injection （10mg/kg, i.p.） and fed with normal diet. The atherosclerosis lesion in aortas was observed by Sudan IV staining. Serum total cholesterol, triglyceride （TG）, TNF-α and activity of post-heparin lipoprotein lipase （LPL） were measured at the end of the 4th and 8th week after an overnight fast. Results： Compared with high-fat diet group, the area of atherosclerosis lesion, serum TG and TNF-α were markedly increased in rabbits of inflammation group, and the activity of LPL was decreased remarkably. Serum TNF-α level was negatively correlated with the activity of post-heparin LPL （r=0.708, P〈0.01）. The area of atherosclerosis, serum TG and TNF-α were decreased in aspirin and PNS group compared with that in inflammation group, and the activity of LPL was increased remarkably. Compared with control group, serum TG and TNF-α were markedly increased in simple-inflammation group, while LPL activity was decreased. Atherosclerotic lesion did not occur in simple-inflammation group. Conclusion： Persistent systemic inflammation could accelerate the formation of atherosclerosis lesion in aortas, which partly depend on the decreasing of the activity of post-heparin lipoprotein lipase. PNS could improve the changes caused by inflammation.

Transformation of Compound K from Saponins in Leaves of Panax notoginseng by Immobilized β-Glucanase

Objective To prepare an active anti-tumor component,compound K(C-K),from saponins in leaves of Panax notoginseng(SLPN) using immobilized β-glucanase.Methods Two entrapments,alginate gel-1(Alg 1) and alginate gel-2(Alg 2),were evaluated for their ability to immobilize β-glucanase.The amount and purity of C-K obtained from the transformation process were analyzed by HPLC,and the immobilizing parameters were optimized.Results β-Glucanase can be immobilized and reused with either of the entrapment.However,using Alg 1 resulted in higher enzyme activity than Alg 2.The optimal concentration of the immobilized enzyme was 10%;The optimal crosslinking time was 4–6 h;and the optimal concentration of the crosslinking agent was 6%– 7%.Conclusion Immobilized β-glucanase shows sustained enzyme activity,good ethanol tolerance,and was reusable for the preparation of C-K from SLPN.

Attenuation of Brain Inflammatory Response after Focal Cerebral Ischemia/Reperfusion with Xuesaitong Injection (血塞通注射液) in Rats

Objective： To investigate the neuro-protective effect of Xuesaitong Injection （血塞通注射液, XST） on brain inflammatory response after transient focal cerebral ischemia/reperfusion in rats. Methods： Focal cerebral ischemia/reperfusion models of male rats were induced by transient occlusion for 2 h of middle cerebral artery （MCA） which was followed by 24 h reperfusion. XST was administered through intraperitoneal injection of 25 mg/kg or 50 mg/kg at 4 h after the onset of ischemia. After reperfusion for 24 h, the neurological function score was evaluated, the brain edema was detected with dry-wet weight method, the myeloperoxidase （MPO） activity and the expression of intercellular adhesion molecule-1 （IOAM-l） of ischemic cerebral cortex and caudate putamen was determined by spectrophotometry and immunohistochemistry respectively. Results： XST not only lowered neurological function score at the dose of 50 mg/kg, but reduced brain edema and inhibited MPO activity and IOAM-1 expression as compared with the ischemia/reperfusion model group （P〈0.01）. Conclusion： XST has a definite effect on inhibiting the expression of IOAM-1 and neutrophil infiltration in rats with cerebral ischemia/reperfusion when treatment started at 4 h after ischemia onset, and also attenuates inflammation in the infarcted cerebral area.