| Objective:The perimenopausal depression rats model was established by bilateral ovariectomy(OVX)and chronic unpredictable mild stress(CUMS).To observe the damage of hippocampal neurons,to study the improvement of biochanin A(Bioch A)on perimenopausal depression rats model,and to explore possible mechanism.Methods:The female rats were randomly divided into six groups : sham group,model group,Bioch A low dose group(10mg/kg),Bioch A medium dose group(20mg/kg),Bioch A high dose group(40mg/kg)and fluoxetine group(2mg/kg).The rat model of perimenopausal depression was established by two steps of OVX and CUMS.Each administration group was intragastrically administered 1 hour before daily stress,while the sham group was given equal volume(1ml/100g)of sodium carboxymethyl cellulose.Rats in the model group and the treatment groups received 21 days of different stress.Estradiol(E2)and luteinizing hormone(LH)were measured by enzyme linked immunosorbent assay(ELISA).The body weigh and open box experiment and forced swimming and sucrose preference test experiment were used to observe the behavioral changes of rats.The contents of dopamine(DA),norepinephrine(NA)and 5-hydroxytryptamine(5-HT)in hippocampus of rats were determined by high performance liquid chromatography-electrochemical detection method.The changes of hippocampal neurons were observed by hematoxylin eosin staining and the expression of tryptophan hydroxylase in hippocampus was detected by immunohistochemistry.The expression of brain-derived neurotrophic factor(BDNF)and tyrosine protein kinase B(Trk B)m RNA were measured by real time PCR.The expression of protein kinase A(PKA)in hippocampus,p-PKA,c AMP response element binding protein(CREB),p-CREB,BDNF,Trk B,NOD-like receptors protein(NLRP1),interleukin-1 converting enzyme(Caspase-1),Apoptosis-associated speck-like protein containing(ASC)were detected by western blot.Results:1)ELISA test for E2 and LH: Compared with sham operation group,E2 were decreased in model group,LH were increased(P<0.01);compared with model group,E2 were increased,LH were decreased after treatment with Bioch A and fluoxetine(P<0.05);2)BW observation: There was no significant difference in body weight between the two groups before modeling.On the 21 st day,compared with sham group,the other groups lost weight(P<0.05);after three weeks of treatment,compared with model group,the rats gained weight after treatment with Bioch A and fluoxetine(P<0.05);3)Behavioral experiments observation: Compared with sham group,the horizontal and vertical scores of the rats in the model group were markedly decreased,and the immobility time of forced swimming was significantly increased,reduced percentage of sucrose preference(P<0.05);Compared with model group,after treatment with Bioch A and fluoxetine,the horizontal and vertical scores of depressive rats increased,and the immobility time of forced swimming increased(P<0.05);4)High performance liquid chromatography-electrochemical detection test results: Compared with sham group,the contents of DA,NA and 5-HT in the model group were decreased;Compared with model group,the contents of 5-HT in the drug group were increased after treatment with Bioch A and fluoxetine;5)Pathological experiments observation: Compared with sham group,the hippocampal neurons in the model group were damaged,atrophied and decreased in number;Compared with model group,after treatment with Bioch A and fluoxetine,the neuronal damage in hippocampus tissue was reduced;6)Immunohistochemistry result: Compared with sham group,the expression of TPH was decreased(P<0.05);Compared with model group,the expression of TPH in the model group was increased after treatment with Bioch A and fluoxetine;7)Real time PCR test results: Compared with sham group,the expression of BDNF and Trk B m RNA in hippocampus of the model group decreased in different degrees(P<0.05);Compared the model group,after treatment with Bioch A and fluoxetine,the expression of BDNF and Trk B m RNA in the drug group increased to different degrees(P<0.05 or P<0.01);8)Western blot test results: Compared with sham group,the PKA and CREB protein phosphorylation levels and BDNF and Trk B protein expression levels in the hippocampus of the model group decreased to different degrees(P<0.05),NLRP-1,ASC and Caspase-1 protein expression levels increased(P<0.05);Compared with model group,after treatment with Bioch A and fluoxetine,PKA and CREB protein phosphorylation levels and BDNF and Trk B protein expression levels increased to different degrees(P<0.05),the NLRP-1,ASC and Caspase-1 in the hippocampus were decreased(P<0.05).Conclusion:Bioch A can reduce depressive symptoms in perimenopausal rats.Its mechanism is mainly related to reducing hippocampal neuronal damage,increasing hippocampal 5-HT content and up-regulating hippocampal c AMP-CREB-BDNF signal pathway protein expression. |
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