Study on the mechanisms of acupuncture combined with paroxetine in the treatment of mild to moderate depression based on DNA methylation analysis.

Objectives: To explore the therapeutic effect of acupuncture combined with paroxetine for mild to moderate depression and the regulatory role of brain derived neurotrophic factor (BDNF) in patients based on DNA methylation.

Methods: A total of 66 patients with mild to moderate depression who met the inclusion and exclusion criteria were randomly divided into an observation (acupuncture+medication) group and a control (medication) group, with 33 patients in each group, and other 25 healthy volunteers were taken as the healthy group. The patients of the control group were treated by oral administration of paroxetine 20 mg/d for 4 weeks. The patients of the observation group were treated by acupuncture stimulation of Zhongwan (CV12), Qihai (CV6), Zusanli (ST36), Sanyinjiao (SP6), Shangxing (GV23), Shuigou (GV26), Shaoshang (LU11), Yinbai (SP1) and Daling (PC7) (for 20 min, 3 times a week for 4 weeks) on the basis of medication treatment (the same as that of the control group). Before treatment, 2 and 4 weeks of treatment, and 2 weeks of follow-up, the therapeutic effect was assessed using Hamilton Depression Scale 17 (HAMD-17). The SPSS25.0 software was used to form a randomized grouping and to randomly select 25 patients from the observation group and 25 patients from the control group for blood collecting and data analysis. The blood samples were taken for assaying serum BDNF content and the methylation degree of BDNF gene promotor I with ELISA and MassARRAY techniques, respectively.

Results: 1) In comparison with those before treatment, the total score of HAMD-17, sleep disorder factor score, and anxiety somatization factor score of both the observation and control groups were significantly decreased after 2 and 4 weeks of treatment, and 2 weeks of follow-up (P<0.05), except sleep disorder factor score in the control group after 2 weeks of the treatment. Compared with the same time-points of the control group, the HAMD-17 total score and sleep disorder factor score of the observation group were decreased after 2 and 4 weeks of treatment, and 2 weeks of follow-up (P<0.05), while the anxiety somatization factor score was evidently decreased after 2 weeks of treatment (P<0.05). 2) Following 2 weeks of treatment, the total effective rate and markedly effective rate of the observation group were 80%(24/30)and 36.67% (11/30), respectively, being significantly higher than those ［(26.67% and 0 %)］ of the control group. After 4 weeks of treatment, the markedly effective rate of the observation group was 70.00% (21/30), being significantly higher than that 40% (12/30) of the control group (P<0.05), while the total effective rates of the observation and control groups were the same (100%). 3) Before the treatment, comparison among the healthy, observation and control groups showed no statistical significance in the methylation degree of each site (CpG1.2, CpG5.6, CpG8.9, CpG26, CpG27, CpG31, and CpG33.34) of BDNF gene promotor I, while after 4 weeks of the treatment, the methylation degree of CpG31 was considerably lower in the observation group than in the control group (P<0.05). 4) Before the treatment, the contents of serum BDNF of both observation and control group had no significant difference, but were evidently lower than that of the healthy group (P<0.05). Compared with that before treatment, the serum BDNF contents in both observation and control groups were significantly increased after the treatment (P<0.05), and was significantly higher in the observation group than in the control group (P<0.05). 5) The correlation analysis showed a negative correlation between the BDNF protein content and HAMD-17 score (correlation coefficient ρ=-0.686, P<0.01).

Conclusions: Acupuncture may have an antidepressant role by decreasing CpG31 methylation of BDNF and increasing the serum content of BDNF protein in patients with depression. In addition, acupuncture combined with paroxetine has more advantages in treating mild to moderate depression than oral paroxetine alone, and can improve sleep disorders and anxiety somatization symptoms more quickly.