Study On The Correlation Of Non-suicidal Self Injury With SLC6A4 Promoter DNA Methylation In Children And Adolescent With Bipolar Depression

Objective:To explore the correlation of non-suicidal self injury(NSSI)with SLC6A4promoter DNA methylation in children and adolescents with bipolar depression.Methods:A total of 48 children and adolescent bipolar patients attending the Department of Clinical Psychology of the People’s Hospital of Xinjiang Autonomous Region,who had bipolar disorder according to the International Classification of Diseases,Tenth Revision(ICD-10)and also had depressive episodes according to the 24 item version score>20 of the Hamilton Depression Inventory,were chosen for inclusion.Based on the presence or absence of non-suicidal self-injurious behaviour,33 cases were allocated to the treatment group and 15cases to the control group,Blood specimens of patients were collected.Negative life events were rated using the Adolescent Life Events Scale(ASLEC),methylation level of SLC6A4promoter region gene was detected by pyrophosphate sequencing.The statistical software SPSS26.0 was used to analyze the data,which included the t-test for measurement data and the chi-square test for count data,binary logistic regression for the analysis of factors influencing NSSI in children and adolescents with bipolar depression,and Spearman correlation analysis method for the analysis of correlation between DNA methylation in the promoter region of SLC6A4 and negative life events in children and adolescents with bipolar depression.Rusults:(1)There was no statistically significant difference between the groups of children and adolescents with bipolar depression who had NSSI and those who had not in terms of age,gender,education level,only child status,or family history(P(29)0.05).(2)There was a statistically significant difference between the two groups in the Cp G2 locus(P(27)0.05),when comparing the methylation levels of SLC6A4 promoter region in the children and adolescents bipolar depression patients with and without NSSI.However,the differences in the other Cp G sites were not statistically significant(P(29)0.05).(3)The results of Logistic regression analysis of NSSI behavior in children and adolescents with bipolar depression revealed that methylation of the Cp G2 locus in the promoter region of the SLC6A4 gene(P=0.022,OR=0.090,95%CI:0.011~0.712)was a Independent influencing factor for NSSI behavior in these patients.(4)There was a statistically significant difference between the Adolescent Life Events Scale(ASLEC)scores of the children and adolescent bipolar depression patients with and without NSSI group(P(27)0.05).(5)The correlation analysis between the methylation levels of each Cp G site and the ASLEC factor scores in the group with and without NSSI showed that there was a correlation between the methylation levels of Cp G3 and Cp G4 sites and the factor scores of loss and health adaptation in the group with NSSI(r_svalues are:-0.409,0.590,0.357,P(27)0.05);There was a correlation between methylation levels of Cp G3,Cp G4,Cp G5 sites and factor scores such as interpersonal relationship and other in the group without NSSI(r_svalues are:0.607,0.573,-0.531,P(27)0.05).Conclusion:(1)There may be an correlation between NSSI behavior and DNA methylation in the SLC6A4 promoter region in children and adolescents with bipolar depression.(2)Methylation of the Cp G2 locus in the promoter region of the SLC6A4 gene may influence the occurrence of NSSI in chidren and adolescent bipolar depression patients.(3)Children and adolescent bipolar depression patients with NSSI may experienced more negative life events than children and adolescent bipolar depression patients without NSSI.(4)Negative life events may correlate with the methylation levels of Cp G3,Cp G4,and Cp G5 sites in the SLC6A4 promoter region of bipolar depression in children and adolescents with and without NSSI.