Correlation Between Thalamus-Related Functional Connectivity and Serum BDNF Levels During the Periovulatory Phase of Primary Dysmenorrhea.

Fang Han,Ling Yang,Ke Wang,Jing Yang,Ming Zhang,Wanghuan Dun,Jixin Liu,Hongjuan Liu

doi:10.3389/fnhum.2019.00333

Abstract

The thalamus is a key region for the transmission of nociceptive information in the central modulation of pain and has been studied in the setting of numerous chronic pain conditions. Brain-derived neurotrophic factor (BDNF) is considered an important modulator for mediating nociceptive pathways in chronic pain. The present study aimed to investigate whether there was thalamus-related abnormal functional connectivity or relevant serum BDNF level alterations during periovulation in long-term primary dysmenorrhea (PDM). Thalamic subregions were defined according to the Human Brainnetome Atlas. Functional connectivity analyses were performed in 36 patients in the periovulatory phase and 29 age-, education-, and gender-matched healthy controls. Serum BDNF levels were evaluated by enzyme-linked immunosorbent assay and a significantly higher BDNF level was detected in PDM patients. Compared with HCs, PDM patients had abnormal functional connectivity of thalamic-subregions, mainly involving with prefrontal cortex, sensorimotor cortex, and temporal cortex. In addition, the functional connectivity of thalamic-subregions showed significant interactive effect correlated with serum BDNF level between PDM and HCs. It has been suggested that there were maladaptive or adoptive alteration associated with chronic menstrual pain even without the ongoing menstrual pain. BDNF might play a role in the development and chronicity of central nervous system dysfunction. These findings provided more accurate information about the involvement of the thalamus in the pathophysiology of PDM.

Highlights

Primary dysmenorrhea (PDM) is an abnormal cramping pain that manifests with the onset of menstruation in every cycle but without organic etiology, which may impact 20–90% of females and is considered to be the most common gynecological disorder in reproductive age (Dawood, 2006; Morrow and Naumburg, 2009)
No differences in visual analog scale (VAS) scores were found during periovulation between the two groups since all subjects reported a lack of pain (i.e., 0)
Correlation analysis revealed a positive association between VAS scores of the menstruation period (VAS-MENS) and serum Brain-derived neurotrophic factor (BDNF) levels in primary dysmenorrhea (PDM) subjects; r = 0.424, p < 0.05

Summary

Introduction

Primary dysmenorrhea (PDM) is an abnormal cramping pain that manifests with the onset of menstruation in every cycle but without organic etiology, which may impact 20–90% of females and is considered to be the most common gynecological disorder in reproductive age (Dawood, 2006; Morrow and Naumburg, 2009). It’s evidenced by a rodent experiment that inhibition of thalamic sensory neurons was in part responsible for the motor cortex stimulationinduced antinociception (Pagano et al, 2012) These studies suggested that thalamic served important functions in pain processing, involving nociceptive perception, and modulation. Previous studies have reported altered brain circuits in PDM to mostly be involved with pain pathways (Tu et al, 2009, 2010, 2013; Vincent et al, 2011; Liu et al, 2016; Wei et al, 2016a), investigating features of thalamus-related pain-modulation that may further elucidate the central pain pathway responsible for the manifestation of menstrual pain

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