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Enriched environment fails to increase meningitis‐induced neurogenesis and spatial memory in a mouse model of pneumococcal meningitis
Author(s) -
Tauber Simone C.,
Bunkowski Stephanie,
Ebert Sandra,
Schulz Daniela,
Kellert Benedikt,
Nau Roland,
Gerber Joachim
Publication year - 2009
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.22010
Subject(s) - neurogenesis , dentate gyrus , meningitis , morris water navigation task , streptococcus pneumoniae , progenitor cell , water maze , elevated plus maze , immunology , biology , hippocampus , medicine , neuroscience , microbiology and biotechnology , surgery , anxiety , stem cell , psychiatry , antibiotics
An increase in adult neurogenesis was observed after exposure to enriched environment (EE) and during reconvalescence from experimental pneumococcal meningitis. This study investigated neurogenesis and spatial learning performance 5 weeks after bacterial meningitis and exposure to EE. C57BL/6 mice were infected by intracerebral injection of Streptococcus pneumoniae and treated with ceftriaxone for 5 days. Forty‐eight hours after infection, one group (n = 22) was exposed to EE and the other group (n = 23) housed under standard conditions. Another set of mice was kept under either enriched (n = 16) or standard (n = 15) conditions without bacterial meningitis. Five weeks later, the Morris water maze was performed, and neurogenesis was evaluated by means of immunohistochemistry. Mice housed in EE without prior bacterial infection displayed both increased neurogenesis and improved water maze performance in comparison with uninfected control animals. Bacterial meningitis stimulated neurogenesis in the granular cell layer of the dentate gyrus: with standard housing conditions, we observed a higher density of BrdU‐immunolabeled and TUC‐4‐expressing cells 5 weeks after induction of bacterial meningitis than in the noninfected control group. EE did not further increase progenitor cell proliferation and neuronal differentiation in the subgranular cell layer of the dentate gyrus after bacterial meningitis in comparison with infected mice housed under standard conditions. Moreover, the Morris water maze showed no significant differences between survivors of meningitis exposed to EE and animals kept in standard housing. In summary, exposure to EE after pneumococcal meningitis did not further increase meningitis‐induced neurogenesis or improve spatial learning. © 2009 Wiley‐Liss, Inc.