RESUMO
Objective:To design Keap1-tat peptide and explore its neuroprotective role on hipocampal CA1 neuron,as well as the effect on spacial learning and memory function following global cerebral ische-mia.Methods:Adult male Sprague Dawley (SD)rats were subjected to global cerebral ischemia (GCI) by four-vessel occlusion for 1 5 min and randomly divided into five groups:sham,sham+Keap1-tat,is-chemia/reperfusion (I/R),Keap1-tat peptide-and vehicle-administrated groups.For Keap1-tat or vehi-cle groups,the rats were treated with Keap1-tat (30,50,1 00 μg in 5 μL 0.9%saline)or the same vo-lume vehicle by intracerebroventricular injection (icv)30 min prior to ischemia.Cresyl violet staining was used to observe the surviving neurons and 4-hydroxy-2-noneal (4-HNE ) and 8-hydroxy-2′-deox-yguanosine (8-OHdG)immunostaining were used to detect the change of markers response to oxidative stress in hippocampal CA1 region.The spatial learning and memory function of the rats was evaluated using Morris water maze.Results:Compared with sham group,the number of surviving neurons in ische-mia-reperfusion and vehicle groups significantly decreased in the hippocampal CA1 region (P<0.05 ), while administration of Keap1-tat significantly decreased the damage following GCI (P<0.05),and the dose of 50 μg existed the most effective neuroprotective role.Furthermore,immunostaining intensity of 4-HNE and 8-OHdG,markers of oxidative stress damage attenuated by Keap1-tat peptide as compared with vehicle group in CA1 region.Of significant interest,the time of finding underwater platform in Keap1-tat group animals was significantly short,and after removing the platform,the probe time of Keap1-tat group animals in the original quadrant where the platform was significantly increased compared with that of vehi-cle and I/R group animals (P<0.05).Conclusion:Keap1-tat peptide can effectively attenuate neuro-nal damage in hippocampal CA1 region and improve learning and memory function,which might bedue to the attenuation of oxidative stress caused by GCI.
RESUMO
Objective To explore the neuroprotective role of Genistein (GEN) on hippocampal CA1 neurons and the possible mechanism following global cerebral ischemia ( GCI) in rats.Methods Seventy five rats were subjected to global cerebral ischemia ( GCI ) by four-vessel occlusion and randomly divided into five groups , sham, ischemia/reperfusion (I/R), GEN, ICI 182,780 and vehicle groups.Fluoro-Jade B and neuron-specific nuclear-binding protein ( NeuN) staining was used to observe CA 1 neuronal survival .TUNEL was used to detect apoptotic neurons .Spatial learning and memory function of the rats were evaluated by Morris water maze .Results The best dose of neuroprotective role of GEN was 1.0mg/kg body weight.Compared with sham, TUNEL-positive neurons in the hippocampal CA1 region increased significantly in I/R and vehicle groups (P<0.01), while post-treatment with GEN (1.0mg/kg) at 5min after ischemia by tail vein injection decreased markedly (P<0.01).Treatment of 1.0mg/kg GEN markedly attenuated spatial learning and memory deficits of the rats after ischemic insult compared to I /R group.Furthermore, ICI 182,780 significantly abolished the neuroprotective role of GEN (P <0.01).Conclusion The low-dose (1.0mg/kg) GEN significantly attenuates neuronal damage and cognitive deficits following GCI in rats , and the mechanism may be involved in estrogen receptor activity.