Introduction: Primary dysmenorrohoea is a common gynecological disease and chronic pain disorder. Moxibustion, a form of traditional Chinese medicine therapy, has proven to be effective for primary dysmenorrohoea. However, the central mechanisms of primary dysmenorrohoea and moxibustion for primary dysmenorrohoea are still unclear. This study aims to explore the potential central mechanism of primary dysmenorrohoeaand clarify the possible mechanism of moxibustion for relieving pain.
Materials and methods: A total of 23 primary dysmenorrohoea patients and 23 matched healthy controls (HCs) were enrolled. For primary dysmenorrohoea patients, resting-state functional magnetic resonance imaging (rs-fMRI) data were collected pre- and post-moxibustion treatment of 3 consecutive menstrual cycles, respectively. For HCs, rs-fMRI data were collected in the baseline. The resting-state functional connectivity strength (rs-FCS) analysis and the resting-state functional connectivity (rs-FC) analysis based on the region of interest (ROI) were combined to be conducted.
Results: Compared to HCs, primary dysmenorrohoea patients showed weaker rs-FCS in the left inferior frontal gyrus (IFG). After the moxibustion treatment, rs-FCS in the left IFG was increased with clinical improvement. Then, the left IFG was chosen as ROI, and the rs-FC analysis was conducted. It showed that the left IFG rs-FC in the bilateral anterior cingulate cortex (ACC)/middle cingulate cortex (MCC), the left posterior cingulate cortex (PCC)/precuneus (PCU), and the left parahippocampal gyrus (PHG) decreased after moxibustion treatment, most of which belong to the default mode network (DMN).
Conclusion: Our results highlight the role of the left IFG and the DMN in primary dysmenorrohoea. Specifically, the central mechanism of moxibustion for analgesia may be related to modulating the disorders of the reappraisal and processing of pain stimuli through influencing the cognition of pain.