Elevated Plasma IL-6 Coincides with Activation of STAT3 in PBMC after Acute Resistance Exercise

Introduction Changes in plasma concentrations of anti-inflammatory cytokines, such as interleukin-6 (IL-6) and IL-10, after acute resistance exercise (RE) have been widely explored. Whether observed changes in plasma cytokine concentration correspond to the activation of anti-inflammatory signaling pathways in immune cells after acute RE is unknown. This study aimed to determine if changes in plasma cytokines after acute RE resulted in the activation of anti-inflammatory signaling pathways in peripheral blood mononuclear cells (PBMC). Methods Healthy young males (N = 16; age = 23.5 ± 2.7 yr; BMI = 22.4 ± 1.7 kg·m-2) participated in a single session of whole-body RE (4 sets of 4 different exercises at 70% 1-repetition maximum with the last set to failure) and a sedentary control (CON) condition in a randomized crossover design. Blood samples were collected at several time points before and after the exercise bout. Results Higher plasma IL-6, IL-10, and IL-1 RA concentrations were observed after RE compared with CON. Phosphorylation of STAT3 and protein expression of SOCS3 in PBMC were increased in RE compared with CON. The elevation of plasma IL-6, but not IL-10, coincided with the activation of STAT3 signaling in PBMC. Conclusions These results highlight a potential mechanism by which RE may exert anti-inflammatory actions in circulating immune cells.