Mechanisms of motor symptom improvement by long-term Tai Chi training in Parkinson's disease patients

Abstract

Background: Tai Chi has been shown to improve motor symptoms in Parkinson's disease (PD), but its long-term effects and the related mechanisms remain to be elucidated. In this study, we investigated the effects of long-term Tai Chi training on motor symptoms in PD and the underlying mechanisms.

Methods: Ninety-five early-stage PD patients were enrolled and randomly divided into Tai Chi (n = 32), brisk walking (n = 31) and no-exercise (n = 32) groups. At baseline, 6 months and 12 months during one-year intervention, all participants underwent motor symptom evaluation by Berg balance scale (BBS), Unified PD rating-scale (UPDRS), Timed Up and Go test (TUG) and 3D gait analysis, functional magnetic resonance imaging (fMRI), plasma cytokine and metabolomics analysis, and blood Huntingtin interaction protein 2 (HIP2) mRNA level analysis. Longitudinal self-changes were calculated using repeated measures ANOVA. GEE (generalized estimating equations) was used to assess factors associated with the longitudinal data of rating scales. Switch rates were used for fMRI analysis. False discovery rate correction was used for multiple correction.

Results: Participants in the Tai Chi group had better performance in BBS, UPDRS, TUG and step width. Besides, Tai Chi was advantageous over brisk walking in improving BBS and step width. The improved BBS was correlated with enhanced visual network function and downregulation of interleukin-1β. The improvements in UPDRS were associated with enhanced default mode network function, decreased L-malic acid and 3-phosphoglyceric acid, and increased adenosine and HIP2 mRNA levels. In addition, arginine biosynthesis, urea cycle, tricarboxylic acid cycle and beta oxidation of very-long-chain fatty acids were also improved by Tai Chi training.

Conclusions: Long-term Tai Chi training improves motor function, especially gait and balance, in PD. The underlying mechanisms may include enhanced brain network function, reduced inflammation, improved amino acid metabolism, energy metabolism and neurotransmitter metabolism, and decreased vulnerability to dopaminergic degeneration. Trial registration This study has been registered at Chinese Clinical Trial Registry (Registration number: ChiCTR2000036036; Registration date: August 22, 2020).

Keywords: Brain network; Mechanism; Motor symptoms; Parkinson’s disease; Tai Chi.

Fig. 1

Flow chart of patient recruitment and follow-ups

Fig. 2

Changes of motor symptoms between groups and related fMRI changes. a–d Changes of rating scales in a Berg Balance Scale, b UPDRS total Score, c UPDRS Part III, and d Timed Up and Go Test in the 3 groups. Data are shown as mean ± SEM. e–h Neural networks associated with the longitudinal changes of rating scales from 12-month to baseline after Tai Chi training. Bright yellow indicates more positive association between neural networks and changes of rating scales. e Visual network associated with Berg Balance scale; f default mode network associated with UPDRS total score; g Ventral salient network associated with UPDRS total score, but the association was not significant; h default mode network associated with UPDRS Part III