The gut microbioma (GM) through the gut-brain axis has been implicated in numerous diseases. GM is known to be associated with the stool condition. We previously reported that the stool condition was associated with pain perception. The aim of this study was to investigate the association between GM composition and pain perception in young healthy subjects.
Methods
A total of 50 healthy volunteers (age 20±0.6 yr.) completed the present study. The pain perceptions were assessed by pressure pain threshold (PPT), current perception threshold (CPT), temporal summation of pain (TSP), and conditioned pain modulation (CPM). During CPT examination, 5, 250, 2,000 Hz stimulation were used to stimulate C, Aδ and Aβ fibers. GM composition was evaluated by using 16S rRNA analysis. Four major phylum (Bacteroidets, Firmicutes, Actinobacteria, Proteobacteria) and bacterium (Bifidobacterium, Lactobacillus, Butyrate-producing, Equol-producing) were selected.
Results
PPT showed a negative association with Bacteroidetes, in contrast to a positive association with Firmicutes. Aδ and Bacteroidetes, and C and Equol-producing bacterium showed negative correlations. Aβ showed a positive association with Bifidobacterium. CPM showed a negative association with Firmicutes. However, TSP did not show any association with the GM composition. In addition, we found that a significant contributor to PPT was Firmicutes, one to C was Equol-producing bacterium, one to Aδ was Bacteroidetes, one to Aβ was Bifidobacterium, and one to CPM was Proteobacteria and Actinobacteria.
Conclusions
The present study showed that the pain perception was significantly associated with the GM composition in young healthy subjects.

THE ASSOCIATION BETWEEN GUT MICROBIOME COMPOSITION AND PAIN PERCEPTION IN YOUNG HEALTHY SUBJECTS