Keap1-tat peptide attenuates oxidative stress damage in hippocampal CA1 region and learning and memory deficits following global cerebral ischemia / 北京大学学报(医学版)

ABSTRACT

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 groupssham,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.