The Effects Of BDNF,ERK,AKT And CAMK On The Improvement Of Cognitive Dysfunction In Rats With Schizophrenia Model By Wendan Decoction

Objective:To study the effects of Wendan Decoction on regulating the expression of brain-derived neurotrophic factor(BDNF),extracellular signal regulated kinase(ERK),protein kinase B(Akt)and calcium ion / calmodulin dependent protein kinaseⅡ(CaMKⅡ)in hippocampal tissue of schizophrenia model rats,to investigate the effects of BDNF and signaling pathway factors ERK,Akt and CaMKⅡ in Wendan Decoction to improve cognitive impairment in schizophrenia model rats.Methods:After 70 SD clean grade rats were adaptively housed for 5 days,they were randomly divided into six groups,10 rats in the normal group,12 rats in the model group,12 rats in the clozapine group,12 rats in the Wendan Decoction high-dose group,12 rats in the Wendan Decoction middle dose group,and 12 rats in the Wendan Decoction low-dose group.Rats in normal group and model group were fed with normal saline,while rats in clozapine group were treated with 20 mg/kg clozapine;Wendan Decoction high dose group,Wendan Decoction middle dose group,Wendan Decoction low dose group were treated with Wendan Decoction at doses of 40,20,10 g/kg,once a day,for 21 consecutive days.2 hours after the end of the last 1treatment,In addition to the rats in the normal group,the rats in all other groups received a single intraperitoneal injection of MK-801(0.6 mg/kg)into the left flank,using this approach to model schizophrenia.The stereotypic behaviors of the rats were observed by experimental researchers,the researchers scored the stereotyped behavior of the rats according to the Sams Dodd and Hoffman criteria;Before and after modeling,the rats were subjected to an Eight arm maze exploration test and an open field test.After 2 days of modeling,the hippocampal tissue of rats was taken out for detection.The expression levels of BDNF,ERK,Akt and CaMKⅡ in the rat hippocampus were detected by real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)technique,Western blot and immunohistochemistry.Results:1.Scoring results of stereotypic behaviors of rats: compared with the blank group after modeling,all other groups showed obvious stereotypic behaviors,meanwhile,the score of stereotypic behaviors was elevated(P<0.01).Compared with the schizophrenia model group,the stereotypic behavior scores at 40,50,and 60 min in the clozapine group were significantly decreased(P<0.05 or P<0.01),those at 30,40,50,and 60 min in the Wendan Decoction group were significantly decreased(P<0.05 or P<0.01),and those at 50 and 60 min in the low dosage group were decreased(P<0.05 or P<0.01).2.Results of the rat open field test: Before modeling,there were no significant differences among the groups.After modeling,the model group traversed the center area more frequently than the normal group(P<0.05);increased total time spent moving in the center zone in the schizophrenia model group(P<0.05).Compared with the schizophrenia model group,the number of times that clozapine group,Wendan Decoction high concentration group,Wendan Decoction medium concentration group and Wendan Decoction low concentration group crossed the central area decreased(P<0.05 or P<0.01);and the total length of time that crossed the central area was significantly reduced in the clozapine group,Wendan Decoction high concentration group and Wendan Decoction medium concentration group(P<0.05).3.Results of the Eight arm maze test in rats: Before modeling,there were no obvious differences among the groups.After the establishment of the schizophrenia model,the frequency of correct memory was decreased in the schizophrenia model group compared with the normal group(P<0.01).Compared with the schizophrenia model group,the frequency of correct memory increased in Wendan Decoction high concentration group,Wendan Decoction middle concentration group and Wendan Decoction low concentration group(P<0.05 or P<0.01),the number of correct memory increased significantly in clozapine group(P<0.01).4.The RT-qPCR method was undertaken to determine the BDNF,ERK,Akt and CaMKⅡmRNA expression in the hippocampus: Compared with the blank group,the mRNA expression of BDNF,ERK,Akt and CaMKⅡ in the hippocampus of the model group was significantly decreased(P<0.01).The expression of BDNF,ERK,Akt and CaMKⅡ mRNA in the hippocampus of rats in the clozapine group,Wendan Decoction high concentration group,Wendan Decoction medium concentration group and Wendan Decoction low concentration group was significantly higher than that in the model group(P<0.05 or P<0.01).5.The protein expression levels of BDNF,ERK(p-ERK),Akt(p-Akt)and CaMKⅡ in the hippocampus of rats were determined by Western blot analysis: The protein expression levels of BDNF,ERK(p-ERK),Akt(p-Akt)and CaMKⅡ were decreased in the schizophrenia model group compared with the blank group(P<0.01).Compared with the schizophrenia model group,the protein expression levels of BDNF,ERK(p-ERK),Akt(p-Akt)and CaMKⅡ were increased in Wendan Decoction high concentration group,Wendan Decoction medium concentration group and Wendan Decoction low concentration group(P<0.05 or P<0.01).The protein expression levels of ERK(p-ERK),p-Akt and CaMKⅡ were increased in clozapine group(P<0.01).6.The expression of BDNF,ERK,Akt and CaMKⅡ in the hippocampal CA1,CA3 and DG was assessed by IHC: Compared with the blank group,the positive expression areas of BDNF,ERK,Akt and CaMKⅡ in the hippocampal tissue of the schizophrenia model group were all significantly decreased(P<0.05 or P<0.01).Compared with the schizophrenia model group,the positive expression regions of BDNF,ERK,Akt and CaMKⅡ in the hippocampus of the drug administration group all increased significantly(P<0.05 or P<0.01).Conclusions:Wendan Decoction may improve the stereotyped behavior and anxiety like behavior of schizophrenia model rats by regulating BDNF,ERK,Akt and CaMKⅡ signaling pathway factors and up regulating the mRNA and protein expression levels of BDNF,ERK,Akt and CaMKⅡ,therefore,we can improve the learning and memory and cognitive function of cognitive impairment model rats with schizophrenia,and then achieve the goal of treating cognitive impairment in schizophrenia.