High intensity interval training control inflammation in mice exposed to Streptococus pneumoniae

Abstract

S.pneumoniae is an important cause of pneumonia. Exercise training is a stimulator of immune system. High Intensity Interval Training (HIIT) have been gain adepts, although their benefits remain unclear. Objective: Evaluate if HIIT prior to S.pneumoniae infection in mice alters lung inflammation. Methods: 38Balb/C mice were divided into 4 groups: Sedentary (SED),HIIT (HIIT), Infection (IF),HIIT+infection (HIIT/IF). HIIT was performed in a treadmill altering 26 session: 1min of 75%¨maximum capacity training and 30s of 50% maximum capacity training, over 4w, 5x/w. 72h after last training, IF groups were challenged with pneumococcal strains M10 (11A)(50 ul/bacteria in saline).Lung function and bronchoalveolar lavage (BAL) were performed 12h after challenge. Afterwards, animals were euthanized, lungs removed to immunohistochemistry and morphometric analysis in lung parenchyma. Results: Pneumococcal inoculation induces an increase in lung resistance (0.74±0.07cmH2O.mL-1.s) and elastance (31.86±8.16 cmH2O.mL-1.s) of respiratory system, in total cells (77.66±54.02x104cells/mL) and neutrophils (73.47±50.88x104cells/mL) in BALF, expression of IL-17 (817.88±217.59mm2) and collagen fibers content in lung parenchyma (17.24±4.54%) (p<0.05). HIIT in inoculated animals resulted in a reduction of all parameters (p<0.05), except for lung resistance. HIIT groups presented increasing expression of IL-1ra (698.64±432.42mm2), CuZnSOD (576.42±138.18mm2), IL-33 (990.07±212.47mm2)(p<0.001). Conclusion: HIIT attenuated inflammatory process induced by S.pneumoniae, increasing antiinflammatory mediators and antioxidant enzymes, reducing proinflammatory mediators.