Open Access Research

Pre-infection physical exercise decreases mortality and stimulates neurogenesis in bacterial meningitis

David Liebetanz1, Joachim Gerber2, Christina Schiffner3, Sandra Schütze4, Florian Klinker1, Hubertus Jarry4, Roland Nau45 and Simone C Tauber3*

Author Affiliations

1 Department of Clinical Neurophysiology, Georg-August-University, Robert-Koch-Strasse 40, 37075 Göttingen, Germany

2 Department of Neurology, Diana Hospital, Dahlenburger Strasse 2a, 29549 Bad Bevensen, Germany

3 Department of Neurology, RWTH University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany

4 Department of Neuropathology, Georg-August-University, Robert-Koch-Strasse 40, 37075 Göttingen, Germany

5 Department of Geriatrics, Ev. Krankenhaus Weende, An der Lutter 24, 37075 Göttingen, Germany

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Journal of Neuroinflammation 2012, 9:168  doi:10.1186/1742-2094-9-168

Published: 10 July 2012

Abstract

Physical exercise has been shown to increase neurogenesis, to decrease neuronal injury and to improve memory in animal models of stroke and head trauma. Therefore, we investigated the effect of voluntary wheel running on survival, neuronal damage and cell proliferation in a mouse model of pneumococcal meningitis. Mice were housed in cages equipped with voluntary running wheels or in standard cages before induction of bacterial meningitis by a subarachnoid injection of a Streptococcus pneumoniae type 3 strain. 24 hours later antibiotic treatment was initiated with ceftriaxone (100 mg/kg twice daily). Experiments were terminated either 30 hours or 4 days (short-term) or 7 weeks (long-term) after infection, and the survival time, inflammatory cytokines and corticosterone levels, neurogenesis in the dentate gyrus of the hippocampal formation and the cognitive function were evaluated in surviving mice. Survival time was significantly increased in running mice compared to control animals (p = 0.0087 in short-term and p = 0.016 in long-term experiments, log-rank test). At the end of the long-term experiment, mortality was lower in trained than in sedentary animals (p = 0.031, Fisher’s Exact test). Hippocampal neurogenesis – assessed by the density of doublecortin-, TUC-4- and BrdU + NeuN-colabeled cells - was significantly increased in running mice in comparison to the sedentary group after meningitis. However, Morris water maze performance of both groups 6 weeks after bacterial meningitis did not reveal differences in learning ability. In conclusion, physical exercise prior to infection increased survival in a mouse model of bacterial meningitis and stimulated neurogenesis in the dentate gyrus of the hippocampal formation.

Keywords:
Exercise; Survival; Mortality; Neurogenesis; Streptococcus pneumoniae; Bacterial meningitis