Strength Training Induced Alterations in Markers of Immune Function

Overview

Exercise has been used to help prevent or slow the progression of inflammation-related disease; however, the mechanism by which this activity may lower concentrations of inflammatory markers remains unclear. The melanocortin receptors 1,3 and 5 (MC1R, MC3R and MC5R) have been shown to function in an anti-inflammatory manner and have the potential to mediate the positive immune adaptations associated with regular physical activity. Preliminary data suggest that MC3R gene expression increases in whole blood after chronic exercise training. The primary aim of the current study is to explore whether this change in gene expression translates into alterations in MC1R, MC3R, or MC5R monocyte surface expression. The secondary aim is to examine the relationship between surface expression of these receptors and circulating inflammatory profiles. The investigators will recruit 42 untrained, healthy males and females aged 18-35 yrs. Half of the group will be placed on an exercise program for 15 weeks. The other half will serve as untrained control subjects. In addition to basic anthropometric measures, the investigators will measure concentrations of inflammatory and anti-inflammatory cytokines (ELISA) and cell surface expression of MC1R, MC3R, and MC5R on monocytes (flow cytometry).

Abstract: Chronic exercise reduces inflammation, but the mechanisms involved are unclear. Recent studies have shown that stimulation of melanocortin 1 and 3 receptors (MC1R and MC3R) on immune cells increases anti-inflammatory cytokine production. PURPOSE: To examine the influence of 12 weeks of resistance training (RT) on body composition, monocyte cell-surface expression of MC1R and MC3R and circulating markers of inflammation. METHODS: Healthy, active males and females (age 20-27 yr) were recruited into a RT group (RE; n = 23) and an active control group (AC; n = 19). RE completed 12 weeks of progressive, periodized RT 3d/wk while AC maintained normal activity habits. Measures of body composition (DXA) were taken and blood was collected prior to (PRE) and following the intervention period (POST). Blood samples were analyzed for monocyte cell-surface expression MC1R, MC3R, MC5R and C-reactive protein (CRP) and the plasma cytokines interleukin 6 (IL-6) and interleukin 10 (IL-10) using flow cytometry and ELISAs respectively.