| Objective:Individual psychological characteristics are considered to be an important factor influencing the effect of intervention.However,there is still a lack of study to explore the role of psychological factors in acupuncture effects and their possible neural mechanism.Pain is an unpleasant feeling and emotional experience,which can provide a good model for studying the role of psychological factors in the effect of acupuncture.In this study,patients with knee osteoarthritis(KOA)were used as the research object.Through the clinical randomized controlled study,combined with the psychological questionnaire,the effect of acupuncture in the treatment of KOA was evaluated,and the relationship between psychological factors and the effects of acupuncture was explored.Based on the resting-state functional magnetic resonance imaging(rs-fMRI),the brain functional activity characteristics of KOA patients and the regulation effect of acupuncture on the brain neural activity was explored.On the premise of clarifying the influence of psychological factors on the effects of acupuncture,this study further explores whether psychological factors affect the clinical effects of acupuncture through the mediation of brain neural activities through the method of mediation analysis.Methods:1.Sixty patients with KOA were randomly divided into true acupuncture group and placebo acupuncture group,with 30 patients in each group.And they received acupuncture or placebo acupuncture intervention for 4 weeks(12 times)respectively.Take the Numerical Rating Scale(NRS)as the main outcome,and the secondary outcome mainly included the Western Ontario and McMaster Universities Osteoarthritis Index(WOMAC),the Short-form of McGill pain questionnaire(SF-MPQ).These outcomes were used to evaluate the improvement of clinical symptoms in KOA patients after intervention.The NEO Five-Factor Inventory(NEO-FFI),Trait Meta-Mood Scale(TMMS),Mindful Attention Awareness Scale(MAAS)and the positive expectations in the Stanford Expectations of Treatment Scale(SETS)were used to evaluate the psychological characteristics of patients with KOA.Correlation analysis was used to clarify the relationship between the changes of clinical symptoms and psychological factors such as personality,emotion,cognition,and positive expectation in patients with KOA.2.Sixty patients with KOA and 40 age-and sex-matched healthy subjects(HC)were included.Based on the analysis method of Amplitude of Low Frequency Fluctuation(ALFF),a comparison was made between KOA patients and HC subjects to investigate the differences in brain regions between KOA patients and HC subjects.FMRI data were collected at baseline and 4 weeks after intervention.ALFF analysis was used to observe the responses of brain functional activity in patients with KOA induced by intervention.All results need to be corrected by the method of Gaussian Random Field theory correction(GRF)(Voxel P<0.05,Cluster P<0.05).3.On the premise of clarifying the influence of psychological factors on the effects of acupuncture,the Mediation Toolbox and the CanlabCore toolkit based on MATLAB platform were used for mediation analysis.The clinical effect was taken as dependent variable,brain functional activity was mediating variable and psychological trait was independent variable.Mediation analysis was used to investigate whether psychological traits affect acupuncture effects by modulating certain functional regions.Results:1.The clinical effect of acupuncture on knee osteoarthritis and the relationship between psychological factors and the effects of acupuncture.In terms of clinical effects:① Comparison within the group found that after 4 weeks of treatment,the NRS,WOMAC and SF-MPQ scores of patients in both groups decreased(P<0.05).However,the NRS score in the real acupuncture group reached the minimum clinically important difference(MCID),while the changes in NRS,WOMAC and SF-MPQ scores in the placebo acupuncture group did not reach the MCID.②Comparison between the groups found that compared with the placebo acupuncture,true acupuncture could significantly reduce the NRS score(P<0.05).The results of correlation analysis showed that:①The changes in positive expectations in the true acupuncture group were negatively correlated with the changes in NRS and SF-MPQ affective scores(r=-0.382,P=0.049;r=-0.416,P=0.031);TMMS-emotional attention was positively correlated with WOMAC scores and SF-MPQ sensory scores(r=-0.408,P=0.035;r=-0.446,P=0.020);there was a negative correlation between the extroversion and the change in WOMAC score(r=0.427,P=0.02).②The change in positive expectations before and after treatment in the placebo acupuncture group was negatively correlated with the change of NRS score(r=-0.428,P=0.033);the openness score was negatively correlated with the change of WOMAC score(r=-0.399,P=0.048).2.Abnormal brain regions in a patient with KOA and brain regions in response to acupuncture.Abnormal brain regions in a patient with KOA:Compared with HC subjects,the functional brain regions with increased ALFF value in KOA patients are mainly in the left inferior frontal gyrus,insula,medial frontal gyrus and other brain areas.Brain regions regulated by acupuncture:After treatment,the ALFF values in the bilateral supplementary motor area,paracentral lobules and other functional brain regions were significantly decreased.Patients in the placebo acupuncture group did not find significant changes in functional brain regions after the placebo acupuncture intervention3.The imaging mechanism of psychological factors affecting the effects of acupuncture on KOA.The results of the mediation analysis showed that:①The right orbital frontal cortex,angular gyrus,and supramarginal gyrus of the true acupuncture group played mediating effects between the changes of positive expectations and the changes of NRS scores.The mediating effect was-0.101,0.198 and 0.125,respectively.Bilateral anterior precuneus played a mediating effect between TMMS-emotional attention and the changes of WOMAC,and the mediating effect was 0.321②In the placebo needle group,the bilateral superior frontal gyrus and supplementary motor area played mediating effects between the changes of positive expectation and NRS,and the mediation effect was 0.156、0.128,respectively.Conclusion:1.Acupuncture can improve the clinical symptoms of knee joint pain and functional dysfunction in patients with KOA.Patients’ relatively positive psychological factors(such as positive expectations,openness.)could help to improve the analgesic effect of acupuncture.2.The functional activity of brain regions such as inferior frontal gyrus,insula and medial frontal gyrus was abnormal in patients with KOA.True acupuncture may play an analgesic effect by regulating the functional activities of the supplementary motor area,paracentral lobules and other brain areas related to physical movement in patients with KOA.3.The brain activity mediated by psychological factors is different from the brain area regulated by acupuncture intervention.The influence of psychological factors on the effect of acupuncture may be multi-dimensional,and the effect of acupuncture can be affected by integrating the activities of neurons in multiple functional brain regions.Psychological factors mainly affect the effects of true acupuncture by regulating the functional activities of brain regions related to cognitive appraisement,decision-making and emotional processing,such as the orbital frontal cortex,angular gyrus,and precuneus.The influence of psychological factors on the effects of placebo acupuncture is mainly related to the brain regions of the superior frontal gyrus,supplementary motor area.These brain regions are mainly related to cognitive memory and motor. |
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