Effects of 15 weeks of resistance exercise on pro-inflammatory cytokine levels in the vastus lateralis muscle of patients with fibromyalgia

Abstract

Background: This study aimed at investigating the effect of a resistance exercise intervention on the interstitial muscle levels of pro-inflammatory cytokines in fibromyalgia (FMS) and healthy controls (CON).

Methods: Twenty-four female patients with FMS (54 ± 8 years) and 27 female CON (54 ± 9 years) were subjected to intramuscular microdialysis of the most painful vastus lateralis muscle before and after 15 weeks of progressive resistance exercise twice per week. Baseline dialysates were sampled in the resting muscle 140 min after insertion of the microdialysis catheter. The participants then performed repetitive dynamic contractions (knee extension) for 20 min, followed by 60 min rest. Pain intensity was assessed with a 0-100 mm visual analogue scale (VAS), and fatigue was assessed with Borg's RPE throughout microdialysis. Dialysates were sampled every 20 min and analyzed with Luminex for interleukin (IL)-1β, tumor necrosis factor (TNF) alpha, IL-6, and IL-8.

Results: At both sessions and for both groups the dynamic contractions increased pain (P < 0.012) and fatigue (P < 0.001). The levels of TNF were lower in the FMS group than the CON group at both sessions (P < 0.05), but none of the other cytokines differed between the groups. IL-6 and IL-8 increased after the dynamic contractions in both groups (P < 0.010), while TNF increased only in CON (P < 0.05) and IL-1β did not change. Overall pain intensity was reduced after the 15 weeks of resistance exercise in FMS (P < 0.05), but there was no changes in fatigue or cytokine levels.

Conclusion: Progressive resistance exercise for 15 weeks did not affect the interstitial levels of IL-1β, TNF, IL-6, and IL-8 in the vastus lateralis muscle of FMS patients or CON.

Trial registration: Clinicaltrials.gov NCT01226784 , registered 21 October 2010.

Keywords: Cytokines; Dynamic contractions; Exercise; Fibromyalgia; Microdialysis; Quadriceps.

Fig. 1

Line and scatter plot showing the median (interquartile range) levels of cytokines during microdialysis in the vastus lateralis muscle of the most painful leg in 24 patients with fibromyalgia (FMS) and 27 healthy controls (CON) before and after 15 weeks of resistance exercise twice per week. a IL-1β, b IL-6, c IL-8, d TNF. Microdialysis was performed for 220 min. During the first 140 min the participant rested (data not shown), whereafter they performed dynamic contractions of the leg (knee extension) for 20 min (EXC) followed by another 60 min of rest (recovery phase). Samples were collected every 20 min and the dialysate sampled between 120–140 min was regarded as baseline (BL). *P < 0.05, both sessions; ^# P < 0.05, only after resistance exercise. IL interleukin, TNF tumor necrosis factor beta

Fig. 2

Line and scatter plot showing the median (interquartile range) pain intensity (VAS 0–100 mm) during microdialysis in the vastus lateralis muscle of the most painful leg in 24 patients with fibromyalgia (FMS) and 27 healthy controls (CON) before (a) and after (b) 15 weeks of resistance exercise twice per week. Microdialysis was performed for 220 min. During the first 140 min the participant rested (data not shown), whereafter they performed dynamic contractions (EXC) of the leg (knee extension) for 20 min followed by another 60 min of rest (RECOVERY). In FMS, but not in CON, pain intensity increased during the dynamic contractions at both sessions (Friedman test: P < 0.001). ^# P < 0.001 compared to 140 min (Dunn’s post-hoc test). VAS visual analogue scale