Electroacupuncture improves learning and memory of diabetic rats with cognitive impairment by affecting hippocampal synaptic plasticity
AIM:To investigate the effects of electroacupuncture(EA)on learning and memory of diabetic rats with cognitive impairment,and to explore its mechanism.METHODS:A rat model of type 2 diabetes mellitus was established with high-sugar and high-fat diet combined with intraperitoneal injection of streptozotocin(30 mg/kg),and then cognition-impaired rats were screened out by the Morris water maze and randomized into diabetic cognitive impair-ment(DCI)group and DCI+EA group,with 10 rats in each group.Ten normal rats served as control group.The acupoints of"Hou San Li","Nei Ting"and"Yi Shu"in the rats of DCI+EA group were needled,while the rats in DCI and control groups were merely immobilized on the rat plates.Before and after modeling as well as treatment,random blood glucose level and escape latency of the rats were detected.After 28 d of EA treatment,the pathological changes of rat hippocampal CA1 region were observed by HE staining,and the synaptic number,postsynaptic density(PSD)thickness and synaptic ultrastructure of hippocampal CA1 region were observed under transmission electron microscope.The mRNA and protein levels of mitogen-activated protein kinase kinase 7(Map2k7),phospholipase A2 group IVE(Pla2g4e),synaptophysin(SYN)and postsynaptic density protein 95(PSD95)were detected by RT-qPCR and Western blot.RESULTS:Com-pared with control group,the rats in DCI group showed significantly higher random blood glucose level(P<0.01),signifi-cantly longer escape latency(P<0.01),and severe pathological impairment in the hippocampal CA1 region.The synaptic ultrastructure of the hippocampal CA1 region was scattered,and both synaptic density and PSD thickness were significant-ly reduced(P<0.01).The hippocampal Map2k7 mRNA and protein levels were significantly increased(P<0.01),while the Pla2g4e,SYN and PSD95 mRNA and protein levels were significantly reduced(P<0.01).Compared with DCI group,the rats in DCI+EA group had significantly lower random blood glucose level(P<0.01),significantly shorter escape laten-cy(P<0.01).The pathological damage of the hippocampal CA1 region was attenuated,the synaptic ultrastructure was sig-nificantly improved,the synaptic density was significantly increased(P<0.05),and the PSD thickness incereased,but the difference was not statistically significant(P>0.05).Moreover,the hippocampal Map2k7 mRNA and protein levels were significantly decreased(P<0.01),the Pla2g4e and SYN mRNA and protein levels were significantly increased(P<0.05 or P<0.01),the PSD95 mRNA expression was significantly increased(P<0.01),and the PSD95 protein expression was increased but without statistical significance(P>0.05).CONCLUSION:Electroacupuncture can improve learning and memory of DCI rats,which may be related to regulating the expression of Map2k7,Pla2g4e SYN and PSD95 in the hippocampus and improving synaptic plasticity.
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万方数据
维普
