Changes In Brain-Derived Neurotrophic Factor Are Correlated With Changes In Il-6 During Aerobic Exercise.

Abstract

The effects of exercise on inflammation are complex. Literature suggests a reduction of chronic inflammation following exercise training, however, following acute bouts of exercise, both pro- and anti- inflammatory responses have been demonstrated. Brain-derived neurotrophic factor (BDNF) has been suggested to have an intermediary role during the inflammatory response to exercise. Therefore, observing the role of BDNF in the post-exercise inflammatory response may allow for a greater understanding of the intricacies of the inflammatory response. PURPOSE: The purpose of this study was to observe the relationship between BDNF and interleukin-6 (IL-6) during aerobic exercise in different environmental conditions. METHODS: Six college aged men (26 ± 3 yrs) completed a VO2max test (48.6 ± 5.7 mL/kg-1/min-1) along with three separate trials in 5°C (LT), 220C (MT), and 35°C (HT). Each trial consisted of cycling for 60 minutes at 60% VO2max, a time to exhaustion trial at 90% VO2max (TTE), and passive recovery for 60 min in the same condition. Blood was obtained before exercise (PRE), after 60 min of cycling (60), after the TTE (90), and after recovery (REC). Blood was analyzed via ELISA for serum and plasma BDNF concentrations and serum IL-6 concentrations. Change scores were calculated as percentages (ΔPRE to 60; ΔPRE to 90; ΔPRE to REC) and analyzed using a Pearson Correlation, with significance defined as α ≥ 0.05. RESULTS: Changes in serum IL-6 (ΔPRE to 60) were significantly (r = .566, p = 0.018) correlated to changes in plasma BDNF (ΔPRE to 60). Changes in serum IL-6 (ΔPRE to 90) were significantly (r = 0.511, p = 0.043) correlated to changes in serum BDNF (ΔPRE to 90). Changes in serum BDNF were not significantly correlated to changes in plasma BDNF. No other significant correlations were observed. CONCLUSION: This study suggests there is a relationship between IL-6 and BDNF. This could lead to better understanding of the mechanism for both IL-6 and BDNF responses due to aerobic exercise. The insignificant correlation between serum and plasma BDNF give evidence that each may represent different pools of BDNF that respond independently to aerobic exercise. This study was partially funded by the Kent State University Research Council