Quercetin reduces susceptibility to influenza infection following stressful exercise

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2008-08, Vol.295 (2), p.R505-R509
• Main Authors: Davis, J. M, Murphy, E. A, McClellan, J. L, Carmichael, M. D, Gangemi, J. D
• Format: Article
• Language: English
• Subjects: Animal Nutritional Physiological Phenomena; Animals; Antiviral Agents - pharmacology; Disease Models, Animal; Disease Susceptibility; Exercise; Influenza; Influenza A Virus, H1N1 Subtype - pathogenicity; Male; Mice; Mice, Inbred ICR; Nutrition; Orthomyxoviridae Infections - physiopathology; Orthomyxoviridae Infections - prevention & control; Orthomyxoviridae Infections - virology; Physical Exertion; Quercetin - pharmacology; Respiratory diseases; Respiratory system; Respiratory Tract Infections - physiopathology; Respiratory Tract Infections - prevention & control; Respiratory Tract Infections - virology; Rodents; Severity of Illness Index; Stress, Physiological - complications; Stress, Physiological - drug therapy; Stress, Physiological - physiopathology; Time Factors
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.90319.2008

1 Division of Applied Physiology, Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia; and 2 Department of Microbiology and Molecular Medicine, Clemson University, Clemson, South Carolina Submitted 27 March 2008 ; accepted in final form 14 June 2008 Exercise stress is associated with increased risk for upper respiratory tract infection. We have shown that exercise stress can increase susceptibility to infection. Quercetin, a flavonoid present in a wide variety of fruits and vegetables, has been reported to inhibit infectivity and replication of a broad spectrum of viruses and may offset the increase in susceptibility to infection associated with stressful exercise. This study examined the effects of quercetin feedings on susceptibility to the influenza virus A/Puerto Rico/8/34 (H1N1) following stressful exercise. Mice were randomly assigned to one of four treatment groups: exercise-placebo, exercise-quercetin, control-placebo, or control-quercetin. Exercise consisted of a run to fatigue ( 140 min) on a treadmill for 3 consecutive days. Quercetin (12.5 mg/kg) was administered via gavage for 7 days before viral challenge. At 30 min after the last bout of exercise or rest, mice ( n = 23–30) were intranasally inoculated with a standardized dose of influenza virus (0.04 hemagglutinating units). Mice were monitored daily for morbidity (time to sickness), symptom severity, and mortality (time to death) for 21 days. Exercise stress was associated with an increased susceptibility to infection [morbidity, mortality, and symptom severity on days 5–7 ( P < 0.05)]; quercetin offset the increase in susceptibility to infection [morbidity, mortality, and symptom severity on days 5–7 ( P < 0.05)] that was associated with stressful exercise. These data suggest that short-term quercetin feedings may prove to be an effective strategy to lessen the impact of stressful exercise on susceptibility to respiratory infection. nutrition; mice; infection; stress; virus Address for reprint requests and other correspondence: J. M. Davis, Univ. of South Carolina, Dept. of Exercise Science, PHRC #301, 921 Assembly St., Columbia, SC 29208 (e-mail: markd{at}gwm.sc.edu )