Oat β-glucan Effects on Neutrophil Respiratory Burst Activity following Exercise

Fatiguing exercise has been associated with a decrease in certain functions of neutrophils, whereas moderate exercise has generally been associated with an increase. Consumption of oat s-glucan (OsG), a soluble fiber and mild immune system enhancer, may offset the immunosuppression associated with intense training and perhaps further enhance the benefits of moderate exercise. Purpose: To test the effects of OsG consumption on neutrophil function and number after both moderate and fatiguing exercise. Methods: Male mice were assigned to one of six treatment groups. Fatiguing exercise mice (Ftg-OsG and Ftg-H2O) ran to volitional fatigue on a treadmill for three consecutive days, and moderate exercise mice (Mod-OsG and Mod-H2O) ran for six consecutive days for 1 h. Control mice (Con-OsG and Con-H2O) were exposed to the treadmill environment but did not run. OsG was consumed in the drinking water (~0.6 mL·d-1) for 10 consecutive days. After rest or exercise on the last day of training, mice were given a 1-mL i.p. injection of thioglycollate. Mice were sacrificed 3 h later; neutrophils were harvested from the peritoneal cavity and counted, and their respiratory burst activity was measured using flow cytometry. Results: Both moderate exercise and OsG increased neutrophil burst activity, whereas fatiguing exercise had no effect. Neutrophil number was increased by fatiguing exercise and OsG, but not moderate exercise. There were no additive effects of exercise and OsG on either of these variables. Conclusion: These data suggest that although not additive in their effects, both OsG and exercise can alter overall neutrophil respiratory burst activity (number and/or function), but only OsG increased both number and function, which may have important ramifications for defense against infection.