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Aim To investigate whether pioglitazone has protective effect against glutamate induced neurotoxicity in cultured cortical neurons and its possible molecular mechanisms underlying pioglitazone's neuroprotective effects.Methods The cortical neurons were taken from newborn rats and used for experiments 7 days after culture.The neurons were randomly divided into control group;glutamate group; glutamate+piogli-tazone group;glutamate+SP600125 group;SP600125 group.Cell viability was determined by MTT.The morphology change of neurons was observed under a fluorescence microscope with fluorescence dye Hoechst 33258.Immunostaining was used to investigate the expression of phospho-ATF2 in neuronal cells.Western blot was performed to investigate the protein level of phospho-JNK1 and total JNK1.Results Pioglitazone markedly reduced the damage of cortical neurons caused by glutamate.Pioglitazone also significantly inhibited glutamate induced up-regulation of phospho-JNK1 protein level and phospho-ATF2 expression.SP600125, an inhibitor of JNK, antagonized the toxicity induced by glutamate.Conclusions Pioglitazone can protect cultured cortical neurons from glutamate induced damage.The protective effect of pioglitazone appears to be associated with inhibiting the c-Jun N-terminal protein kinase signaling pathway.
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AIM To observe the neuroprotective effect and protective mechanisms of ibuprofen on amyloid β-protein fragment 1-40 (Aβ1-40)-induced neurotoxicity in rat hippocampus.METHODS Rats were given ibuprofen (15 mg·kg-1 daily,ig) for 3 weeks prior to icv single dose of Aβ1-40 (5 μL,1 mmol·L-1).Six hours after Aβ1-40 injection,Western blotting was used to determine the expressions of phospho-MAP kinase kinase (MKK)3/MKK6,phospho-p38 MAP kinase,phospho-MAP kinase activating protein kinase 2 (MAPKAPK2),heat-shock protein 27(Hsp27),procaspase 9,3,and 7 cleavage,and poly (ADP-ribose) polymerase (PARP) cleavage in hippocampal CA1 region.RESULTS Intracerebroventricular injection of Aβ1-40 induced an increase in phosphorylated MKK3/MKK6 and p38 MAP kinase expressions in hippocampal CA1.These increases,in combination with reduced phospho-MAPKAPK2 and phospho-Hsp27 expressions,mediated Aβ1-40-induced the activation of caspases cascades.Ibuprofen (15 mg·kg-1·d-1,3 weeks) significantly prevented Aβ1-40-induced increases in phosphorylated MKK3/MKK6 and p38 MAP kinase expressions.In addition,Aβ1-40-induced decreases in phosphorylated MAPKAPK2 and Hsp27 expressions were abrogated by ibuprofen.Aβ1-40-induced changes in activation of caspases cascades were inhibited by ibuprofen.CONCLUSIONIbuprofen prevents Aβ1-40-induced neurotoxicity through suppression of phosphorylated MKK3/MKK6 and p38 MAP kinase expressions and the up-regulation of phospho-Hsp27 expression.
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AIM To investigate whether Aβ deposit in Alzheimer disease(AD) impairs signal transduction pathway responsible for neuronal survival.METHODSThe rats were randomly divided into six groups:control group and Aβ25-35 group,Aβ25-35+ibuprofen groups (7.5 and 15 mg·kg-1,respectively),Aβ25-35+ibuprofen+LY294002 group,and Aβ25-35+LY294002 group.Rats were given ibuprofen (7.5 and 15 mg·kg-1 daily,ig) for 3 weeks prior to and 1 week after icv single dose of Aβ25-35 (10 μL,1 mmol·L-1).LY294002 was injected icv 1 h before the injection of Aβ25-35.Seven days after Aβ25-35 injection,the hippocampal expressions of P53,Bax,Fas ligand (FasL),Bcl-2 proteins,phospho-Akt/PKB,and phosphorylated 70 ku ribosomal protein S6 kinase (p70S6K) and caspase 3 were determined in the brain tissue preparations from CA1 area with Western blot.The activity of caspase 3 was measured using a caspase 3 colorimetric activity assay kit.RT-PCR was used to show the change of p70s6k mRNA level.RESULTS Aβ25-35 icv injection significantly down-regulated phosphorylated Akt/PKB from 1.32±0.14 to 0.69±0.08 and p70S6K from 0.769±0.028 to 0.479±0.032 in hippocampal CA1 region.These changes were accompanied by increased expressions of the proapoptotic proteins P53,Bax,and FasL and decreased expression of the anti-apoptotic protein Bcl-2 in rat hippocampus.In addition,caspase 3 activity was significantly enhanced in hippocampal CA1 region in Aβ25-35-treated rats compared with control rats.Ibuprofen can reverse these Aβ25-35-induced changes.CONCLUSION Down-regulated anti-apoptotic PI3K/Akt/p70S6K signaling pathway induced by Aβ25-35 in rat hippocampus may contribute to the neuronal damage in AD.Ibuprofen prevents Aβ25-35-induced down-regulation of PI3K/Akt/p70S6K signaling pathway.
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AIM To explore the mechanism of amyloid β-protein fragment 25-35(Aβ25-35)-induced inflammation and apoptosis in rat hippocampus in vivo by studying mitogen-activated protein kinase (MAPK) signaling pathway and the protective effect of anti-inflammatory drug ibuprofen. METHODS Rats were given ibuprofen (7.5 mg·kg-1 daily, ig) for 3 weeks prior to and 1 week after icv single dose of Aβ25-35 (10 μL, 1 mmol·L-1). Seven days after injection, Nissl staining and immunocytochemical technique were employed to determine the morphology of pyramidal neurons and astrocyte infiltration in hippocampal CA1. The expressions of IL-1β, extracellular signal-regulated kinase (ERK), p38 MAPK, PKC, and caspase-3 were determined by Western blot. Reverse transcription-PCR analysis showed changes in IL-1β mRNA level. RESULTS Intracerebroventricular injection of Aβ25-35 elicited astrocyte activation and infiltration and caused a strong inflammatory reaction characterized by increased IL-1β production and elevated IL-1β mRNA level. The inflammatory reaction was accompanied by the loss of pyramidal neurons in hippocampal CA1. The phosphorylation of p38 MAPK was significantly increased, on the other hand, the phosphorylation of ERK was significantly reduced and these were coupled with the increase of caspase-3 expression in hippocampal CA1. Ibuprofen (7.5 mg·kg-1 daily, 4 weeks) significantly reduced Aβ-induced IL-1β expression, caspase-3 expression and p38 MAPK activation. The loss of pyramidal neurons was also significantly attenuated by treatment with ibuprofen. CONCLUSION The activation of p38 MAPK and the down-regulation of ERK play a pivotal role in the inflam-matory response and apoptosis evoked by Aβ25-35 in vivo, which can be prevented by ibuprofen.
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Aim To study the effects of sodium ferulate on A?induced cognitive deficits and expressions of IL-1? and phospho-p38MAPK proteins.Methods Alzheimers disease model of rats was produced by intracerebroventricular injection of A?_(25-35)(10 ?g,once).Morris water maze was used to measure spatial memory performance.Nissl staining and immunohistochemical technique for glial fibrillary acidic protein(GFAP) were employed to determine the morphology of pyramidal neurons and astrocyte infiltration in hippocmpal CA1 regions.The levels of phospho-p38MAPK and IL-1? were determined by Western blot and ELISA method.Reverse transcription-PCR analysis showed changes in FasL mRNA.Results Intracerebroventricular injection of A?_(25-35)in rats resulted in spatial memory impairments shown by longer escape latency and decreased percentage of time spent in the target quadrant.These behavioral dysfunctions were accompanied by astrocyte activation and infiltration,increased IL-1? production and elevated FasL mRNA level,the loss of pyramidal neurons in hippocampal CA1,and the increase of phosphorylated p38MAPK.Oral administration of sodium ferulate(50,100,250 mg?kg~(-1)daily) and ibuprofen 15 mg?kg~(-1)daily markedly improved the memory impairment,attenuated pyramidal neuronal damage,and reversed the A?-induced increases in IL-1? and p38MAPK activation.Conclusion sodium ferulate prevents A?-induced neurotoxicity through suppressions of inflammatory response and the activation of p38MAPK.