Repeated Electroacupuncture Persistently Elevates Adenosine and Ameliorates Collagen-Induced Arthritis in Rats

Tian-Shen Ye,Jian-Qiao Fang,Huan Hu,Zhong-Heng Du,Wen-Xia Xie,Jun-Lu Wang,Zhou-Yang Chen,Zhi-Hui Li,Yong Chen,Ka-Te Huang

doi:10.1155/2016/3632168

Abstract

The aim of this paper was to investigate the effect of repeated electroacupuncture (EA) over 21 days on the adenosine concentration in peripheral blood of rats with collagen-induced arthritis (CIA). Wistar rats were divided into three groups of 6 animals each: sham-control, CIA-control, and CIA-EA. We determined the adenosine concentration in peripheral blood and assessed pathological changes of ankle joints. Quantitative reverse-transcription-polymerase chain reaction was used to determine mRNA levels of ecto-5′-nucleotidase (CD73), adenosine deaminase (ADA), and tumor necrosis factor-alpha (TNF-α). Immunohistochemical staining was used to detect expression of ADA and CD73 in synovial tissue. Repeated EA treatment on CIA resulted in the persistence of high concentrations of adenosine in peripheral blood, significantly reduced pathological scores, TNF-α mRNA concentrations, and synovial hyperplasia. Importantly, EA treatment led to a significant increase in CD73 mRNA levels in peripheral blood but was associated with a decrease of CD73 immunostaining in synovial tissue. In addition, EA treatment resulted in a significant decrease of both ADA mRNA levels in peripheral blood and ADA immunostaining in synovial tissue. Thus, repeated EA treatment exerts an anti-inflammatory and immunoregulatory effect on CIA by increasing the concentration of adenosine. The mechanism of EA action may involve the modulation of CD73 and ADA expression levels.

Highlights

Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily consists of chronic and symmetric polyarthritis
Tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6) expression levels are increased in serum of RA patients or experimental animals with collageninduced arthritis (CIA) [1, 2]
Adenosine concentrations in peripheral blood of rats in the CIAcontrol and CIA-EA groups increased compared to the shamcontrol group (P < 0.01)

Summary

Introduction

Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily consists of chronic and symmetric polyarthritis. Tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6) expression levels are increased in serum of RA patients or experimental animals with collageninduced arthritis (CIA) [1, 2]. The strong expression of TNFα in synovial tissue of RA patients has been demonstrated by the study of Li [3]. In a study carried out by Ouyang et al [5], the investigators found that TNF-α expression levels in blood and synovia of patients with RA significantly decreased after EA treatment, compared to controls. Ouyang et al [6] reported that EA effectively decreased expression levels of the proinflammatory cytokines IL-1 and IL-6 and increased expression levels of the anti-inflammatory cytokines IL-4 and IL-10 in peripheral blood and synovial fluid from patients with RA. Other studies [7, 8] have demonstrated that EA treatment using the Stomach 36 (ST36) acupoint increased

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