Moxibustion for primary dysmenorrhea: A resting-state functional magnetic resonance imaging study exploring the alteration of functional connectivity strength and functional connectivity

Abstract

IntroductionPrimary dysmenorrhea (PDM) is a common gynecological disease and chronic pain disorder. Moxibustion, a form of traditional Chinese medicine therapy, has proven to be effective for PDM. However, the central mechanisms of PDM and moxibustion for PDM are still unclear. This study aims to explore the potential central mechanism of PDM and clarify the possible mechanism of moxibustion for relieving pain.Materials and methodsA total of 23 PDM patients and 23 matched healthy controls (HCs) were enrolled. For PDM 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.ResultsCompared to HCs, PDM 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).ConclusionOur results highlight the role of the left IFG and the DMN in PDM. 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.

Resting-state abnormalities in functional connectivity of the default mode network in migraine: A meta-analysis

“…In our subgroup analysis, we also found abnormalities of FC in other brain regions (inferior frontal gyrus of orbital part and opercular part) of the frontal lobe. These brain regions of rs-FC abnormalities were associated with migraine and other pain disorders in the past studies (Xu et al, 2022;Yang et al, 2022), indirectly suggesting that the frontal cortex plays an important role in pain perception and regulation, and to a certain extent, it is possibly involved in the development of migraine.…”

Scientific Knowledge Graph of Dysmenorrhea: A Bibliometric Analysis from 2001 to 2021

“…FC analysis can explore changes in brain functional activity associated with PDM, by analyzing the strength of the FC relationship between a particular brain region and other brain regions, from a functional integration perspective. 6 The cluster map showed a special protein (annexin a2, ANXA2), relevant to the diagnosis of dysmenorrhea caused by adenomyosis. ANXA2 is a kind of calcium-binding cytoskeleton protein, existing in a variety of cell types, with diverse cellular functions, including angiogenesis, proliferation, apoptosis and cell growth regulation.…”

“… 7 Recently, researchers have even suggested that dysmenorrhea may put women in a state of chronic pain and the chronic pain may lead to an effect on the central nervous system, and then causes pathological changes in brain anatomy structure and function, further aggravating PDM. 6 …”

“…4 The etiology of primary dysmenorrhea is not well defined, but the most recognized explanation attaches dysmenorrhea to the increase of prostaglandins (PGs), particularly PGF 2α, 5 which causes a uterine contraction to limit blood flow and results in cramps. 6 In addition to PGs, vasopressin has also been implicated in the etiology of primary dysmenorrhea, but the involvement of vasopressin remains controversial. Besides, menstrual pain may lead to the development of central sensitivity to pain.…”

Efficacy of acupuncture-related therapy in the treatment of primary dysmenorrhea: A network meta-analysis of randomized controlled trials

“…Common acupuncture techniques for treating PD in clinics include acupuncture (A), acupuncture + moxibustion (A + Mo), moxibustion (Mo), electroacupuncture (El), warm acupuncture (WA), heat-sensitive moxibustion (HsM), ginger-separated moxibustion (GsM), point embedding (PE), acupoint patching (AP), auricular point therapy (APT), and massage therapy (Ma). Acupuncture techniques, whether used alone or in combination, exert good effects in PD treatment [ [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] ]. Nowadays, many acupuncture techniques with different therapeutic advantages are available.…”