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Aim To research the neuroprotective effect of Haikun Shenxi (HKSX) medicated serum on N2a/ App695 cells and the underlying mechanism. Methods HKSX medicated serum was prepared and carbohydrate components in it was analyzed using high performance thin layer chromatography (HPTLC) . N2a/ App695 cells were intervened with HKSX medicated serum, the cytotoxicity of HKSX medicated serum was measured by MTT; AP[_
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Objective: To investigate the protective effect of human lipoxin A4 (LXA4) on N2a cell damage induced by β-amyloid protein 25-35 (Aβ25-35) and the underlying mechanism. Methods: Aβ25-35 was used to treat N2a cells to establish Alzheimer's disease (AD) cell injury model. Meanwhile, LXA4 was added to the experimental group at different concentrations (50, 100 and 200 nmol·L-1 ). MTT assay was used to detect the activity of N2a cells. The apoptosis was detected by Hoechst 33258-PI staining, the expression of P62 and TRAF6 mRNA was detected by RT-PCR, and the expression of P62 and TRAF6 protein was detected by Western blot. Results: Compared with that of the model group, the cell survival rate of LXA4 protective group (50,100 and 200 nmol·L-1 ) increased (P <0. 01) and the apoptosis of N2a cells induced by Aβ25-35 was reduced by LXA4 (100 and 200 nmol·L-1 ) . Compared with that of the model group, the expression of P62-mRNA and protein-P62 of N2a cells treated with Aβ25-35 increased (P <0. 05 or P <0. 01) and the expression of TRAF6-mRNA and protein-TRAF6 of N2a cells treated with Aβ25-35 were reduced (P <0. 05 or P <0. 01). Conclusion: LXA4 has protective effect on N2a cell damage induced by Aβ25-35 , and its mechanism may be related to the up-regulation of P62 gene and down-regulation of TRAF6 gene.
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Objective To discuss the impact of the neurotoxity of bupivacaine and bupivacaine-induced cellular neurotoxicity caused by pretreatment of ganglion (GM-1 )monoglyceride on the ex-pression of caspase-3.Methods The mouse neuroblastoma cells-N2a cells was used as a research object to carry out the following experiments:(1)To observe the damage effects of different concen-trations of bupivacaine on N2a cells and find out the most suitable damage concentration to establish cell damage model.The N2a cells were interacted with bupivacaine with different concentrations [0μmol/L (group C),600 μmol/L (group B1),900 μmol/L (group B2),1 200 μmol/L (group B3), 1 500 μmol/L (group B4),2 000 μmol/L (group B5)]for 6,12,24,36 h and then evaluated by CCK-8 cell survival.Each experiment was repeated three times.The protective function of GM-1 to bupiva-caine-induced N2a cells damage.The N2a cells were treated with different concentrations (0.1μmol/L (group BG1),1.0 μmol/L (group BG2),10 μmol/L (group BG3))of GM-1 pretreatment 24 h,CCK-8 was evaluated in cell viability,Western Blot method was used to detect damaged cells caspase-3 expression levels.Each experiment was repeated three times.Results (1)Bupivacaine could significantly damage N2a cells,the greater the bupivacaine concentration,the longer the action time,the stronger neurotoxicity.(2)GM-1 bupivacaine nerve injury had a significant protective effect in a dose-related manner.The maximum of protective dose of this experiment was 10 μmol/L.Conclusion Bupivacaine can significantly damage N2a cells,correlating with both dose and time double positively,while GM-1 pretreatment significantly reduced the expression of caspase-3 induced by bupivacaine.
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AIM:To explore the role of microRNA-181b (miR-181b) in ischemic injury and autophagy pro-tein 5 (Atg5) levels of mice .METHODS:Oxygen-glucose depletion (OGD) model in N2A cells to mimic ischemic in-jury in vitro was established .A middle cerebral artery occlusion ( MCAO) model to mimic ischemic injury in vivo was also induced in mice.The N2A cell apoptosis after OGD was assessed by in situ cell death detection kit.The Atg5 and caspase-9 expressions were determined by Western blotting .Luciferase reporter assay was performed to identify the direct binding of miR-181b with 3’-UTR of Atg5 mRNA.RESULTS:The alteration of miR-181b expression level by transfection with pre-miR-181b or anti-miR-181b significantly affected N2A cell apoptosis (P<0.05).Accordingly, the changes of miR-181b levels significantly altered the protein level of Atg 5 ( P<0.05 ) .Co-transfection of the luciferase reporters with pre-miR-181b or anti-miR-181b resulted in the inhibition or enhancement of the luciferase activities of luciferase expressing plasmid containing 3’-UTR of Atg5 mRNA (P<0.05).In addition, the miR-181b antagonist significantly reduced the cleaved caspase-9 levels in cerebral ischemic cortex of the mice after MCAO ( P<0.05 ) .CONCLUSION: Down-regulation of miR-181b plays an important role in ischemic injury of mice through regulating Atg 5 protein level.
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Aim To investigate the effect and mecha-nism of valproic acid on neuroglobin expression, and the neuroprotective role of valproic acid against H2 O2-induced neurotoxicity. Methods Western blot, RT-PCR and luciferase assay were used to detect the pro-tein levels, mRNA levels and promoter activity of mouse and human neuroglobin induced by valproic acid. Luciferase assay was used to investigate the role of transcription factor CREB in the up-regulation of neuroglobin by valproic acid. MTT assay was used to evaluate the effect of valproic acid against H2 O2-in-duced neurotoxicity. Results VPA treatment marked-ly increased the protein levels, mRNA levels and pro-moter activity of Ngb in mouse N2 a cells and human SKNSH cells. CREB specific inhibitor KG501 or CREB dominant negative mutant KCREB attenuated VPA-induced Ngb promoter activity. VPA could pro-tect N2a cells from H2 O2-induced neurotoxicity. Con-clusion CREB mediates VPA-induced Ngb up-regula-tion, which may contribute to the neuroprotective effects of VPA in oxidative stress in neurons.
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Researches have shown that melatonin is neuroprotectant in ischemia/reperfusion-mediated injury.Although melatonin is known as an effective antioxidant,the mechanism of the protection cannot be explained merely by antioxidation.This study was devoted to explore other existing mechanisms by investigating whether melatonin protects ischemia/reperfusion-injured neurons through elevating autophagy,since autophagy has been frequently suggested to play a crucial role in neuron survival.To find it out,an ischemia/reperfusion model in N2a cells was established for examinations.The results showed that autophagy was significantly enhanced in N2a cells treated with melatonin at reper-fusion onset following ischemia and greatly promoted cell survival,while autophagy blockage by 3-MA led to the shortened N2a cell survival as assessed by MTT,transmission electron microscopy,and laser confocal scanning microscopy.Besides,the protein levels of LC311 and Beclinl were remarkably increased in ischemia/reperfusion-injured N2a in the presence of melatonin,whereas the expression of p-PKB,key kinase in PI3K/PKB signaling pathway,showed a decrease when compared with untreated subjects as accessed by immunoblotting.Taken together these data suggest that autophagy is possibly one of the mechanisms underlying neuroprotection of melatonin.
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Objective To study the effect of heat shock protein 40(HSP40) and heat shock protein 70(HSP70) on the aggregate formation of mutant huntingtin (htt) and its toxicity in N2a cells. Methods The effect of the over-expression of HSP40 and HSP70 alone or co-over-expression of them on aggregate formation of transfected mutant htt (containing 150 glutamine repeats, 150Q) in N2a cells was detected by fluorescence microcopy and Western blotting. Cell viabilities were detected by MTT assay. Reactive oxygen species (ROS) production was detected by colorimetric method. Results The over-expression of HSP40 and HSP70 alone, especially the co-over-expression of them, dramatically decreases the formation of 150Q htt aggregates in N2a cells. The numbers of aggregates in each group are as follows ( n = 1 000): about 50% in the group of 150Q htt-expressing alone, about 12% in the group of over-expression of HSP40, about 15% in the group of over-expression of HSP70, about 5% in the group of co-over-expression of HSP40 and HSP70. The result of MTT assay shows that the over-expression of HSP40 and HSP70 alone, especially the co-over-expression of them, dramatically increases cell viabilities ( P<0.01, n =3) and reduces the production of ROS ( P<0.01, n =3). Conclusion HSP40 and HSP70 can increase cell viabilities of 150Q N2a cells via inhibiting the aggregates formation of mutant huntingtin and reducing oxidative stress.
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To study the prevention of dauricine (Dau) on bradykinin (BK) induced alteration of intracellular calcium homeostasis and tau phosphorylation, fluorescence spectrophotometer with dual excitation was utilized to measure the intracellular calcium concentration ([Ca2+]i), MTT to detect cell viability and immuncytochemistry to examine tau phosphorylation. The results showed (1) cells treated with BK 1 μmol/L induced a transit increase in [Ca2+]i in all the cell lines detected, among them, the sustained increase of [Ca2+]i level was only seen in PS1Δ9/APPswe cell at 2 h and 24 h after the treatment. Dau (3μmol/L or 6 μmol/L) prevented BK-induced transit and sustained elevation and fluctuation of [Ca2+]i;(2) BK treatment decreased the cell metabolism detected at 2 h in PS1Δ9/APPswe and Dau antagonized the effect; (3) BK induces Alzheimer-like tau hyperphosphorylation at tau-1 epitope and Dau partially antagonized this effect. In conclusion,Dau inhibits BK-induced disturbance in intracellular calcium homeostasis and tau hyperphosphorylation at tau-1 sites.