Inflammatory response to Streptococcus pneumoniae was attenuated by moderate aerobic exercise training

ABSTRACT

Moderate aerobic exercise training may alter immune system. Studies suggested that S. pneumoniae remained an important cause of mortality. Objective: To study mechanisms for attenuating inflammatory process involving pneumococcal infection by moderate aerobic exercise. Methods: 38Balb/C mice were divided into 4 groups Control (C), Moderate Aerobic Exercise Training (MAT), S. pneumonia infection (IF), MAT+IF groups. Moderate intensity treadmill training was performed over 4weeks, 5x/week, 60min/session in MAT groups. After 72h of last exercise training, IF groups were challenged with pneumococcal strains M10 (11A; 50ul/bacteria in saline) and 12h after, lung function and bronchoalveolar lavage (BAL) were performed. Afterwards, animals were euthanized, lungs removed to proceed immunohistochemistry and morphometric analysis in lung parenchyma. Results: Bacterial inoculation resulted in increase in total cells (77.66±54.02x104cells/mL), neutrophils (73.78±50.88x104cells/mL), resistance (0.77±0.08cmH2O.mL-1.s;) and elastance (31.86±8.16cmH2O.mL-1.s) of respiratory system and expression of IL-17 (817.88±217.59mm2)(p<0.05). MAT in animals submitted to bacterial challenge presented a decrease of these parameters (p<0.05). MAT+IF group showed an increase in expression of IL-1ra (886.04±274.07mm2), TLR2 (708.28±161.48mm2) and TLR4 (1444.11±723.92mm2) compared to IF group (p<0.05). Conclusion: These results suggest that MAT attenuated inflammatory process in an animal model of bacterial infection by increasing anti-inflammatory mediators, increasing Toll-like receptors that anticipated host defense, helping in resolution of inflammation.