The Effects Of EA At GV24/GV29 On Morphological Structure And Expression Of 5-HT_1A/1B Receptor Of Hippocampus In CUMS Rats

BackgroundSelective serotonin reuptake inhibitors(SSRIs)are widely applied as antidepressants at present,which can improve signal transmission between nerves by combining with 5-HT transporters and effectively inhibiting the reuptake of 5-TH to accelerate the accumulation among synaptic gaps.It is reported that the delayed onset of SSRIs might be associated with 5-HT1A and 5-HT1B receptor and changes of synaptic plasticity.Our previous clinical study demonstrated that electroacupuncture(EA)at GV24 and GV29 could produce as comparable outcomes as SSRIs at the initial stage in treating mild and moderate depression,but earlier improvement in some symptoms,which inferred that the quick onset of EA might relate to 5-HT1A and 5-HT1B receptor.Functional magnetic resonance imaging(fMRI)in our previous study also detected active hippocampus in patients with mild and moderate depression by EA at GV24 and GV29.According to the information above,in this study,we investigated the effects of EA at GV24 and GV29 on hippocampus synaptic plasticity and expression of 5-HT1A and 5-HT1B receptor in CUMS rats,and explored the central neural mechanism of EA in treating depression.ObjectiveTo explore the effects of EA at GV24 and GV29 on hippocampus morphological structure and expression of 5-HT1A and 5-HT1B receptor in CUMS rats.MethodsCUMS rats were randomly assigned to the EA,the paroxetine and the model groups.After an intervention lasting for 14 days,behavioral indexes of CUMS rats were collected and analyzed,including body weight,food intake,sucrose preference and open field test.We also investigated the changes of RNA expression of 5-HT receptor as well as the morphological structure of synapsis in the CUMS rats'hippocampus.These data were also compared with the control group 's.Results1.Behavioral results.After modeling,the behavioral indexes in the model group,the EA group and the paroxetine group were lower than the blank control group(P<0.05);after intervention,behavioral indexes in the EA group and paroxetine group were both improved and better than the model group;as for the sucrose preference and central time,the improvement in the EA group was earlier than the paroxetine group,but other behavior indexes had no significant difference(P>0.05).2.The expression of 5-HT receptor mRNA in hippocampus.After modeling,all the groups had down-regulated expression of 5-HT1A and 5-HT1B receptor(P<0.05);after intervention,the EA group and the paroxetine group had up-regulated expression of 5-HT1A and 5-HT1B receptor;the EA group had the up-regulated expression of 5-HT1A receptor at the 7th day,which was earlier than the paroxetine group(P<0.05).3.The changes in hippocampus Morphological Structure.The morphological changes of neurons,synaptic structures,mitochondria and lysosomes in the hippocampus of rats were observed after modeling.However,the EA group and the paroxetine group can improve the hippocampus of the above organelles morphological changes.Conclusions1.The behavioral indexes including body weight,food intake,sucrose preference and open field test as well as the changes of RNA expression of 5-HT1A and 5-HT1B receptor in the CUMS rats' hippocampus were lower than the blank control group.2.As for behavioral indexes,including body weight,food intake,sucrose preference and open field test,EA at GV24 and GV29 had as comparable outcomes as those in the paroxetine group,and a conceivably better improvement in the sucrose preference and central time.3.The mechanism of EA at GV24 and GV29 effective anti-depression probably bases on the up-regulated expression of 5-HT1A and 5-HT1B receptor.4.The mechanism of EA at GV24 and GV29 effective anti-depression probably bases on the changes of neurons,synaptic structures,mitochondria and lysosomes in the hippocampus.