辣木种子提取物对小鼠实验性肝损伤的保护作用

目的考察辣木种子提取物对小鼠实验性肝损伤(急性酒精性肝损伤、四氯化碳致急性肝损伤)的保护作用。方法 RT-PCR、Western blotting分别检测小鼠肝组织ADH1和ALDH2 mRNA、蛋白表达。建立小鼠急性酒精性肝损伤模型,测定ALT、AST、ALP、LDH、GSH、MDA水平;建立小鼠四氯化碳致急性肝损伤模型,测定ALT、AST、GSH、MDA、T-SOD、GSH-Px、GR水平,RT-PCR检测C/EBPα、TNF-α、SREBP-1c、COX-2 mRNA表达,HE染色观察小鼠肝组织病理学变化。结果提取物(500 mg/kg)可提高ADH1 mRNA、蛋白表达,但对ALDH2无明显影响。对于急性酒精性肝损伤小鼠,各剂量提取物(125、250、500 mg/kg)降低ALT、AST、ALP、LDH、MDA水平,提高GSH水平;对于四氯化碳致急性肝损伤小鼠,各剂量提取物(32. 5、75、150 mg/kg)降低ALT、AST、MDA、GSHPx水平及COX-2、TNF-α、SREBP-1c mRNA表达,提高T-SOD、GSH、GR水平及C/EBPαmRNA表达,改善肝组织形态。结论辣木种子提取物对小鼠实验性肝损伤有明显保护作用,其机制可能与加快乙醇代谢、缓解炎症反应、抑制脂肪酸和胆固醇合成、改善脂质代谢紊乱有关。

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.