Organotypic hippocampal cultures -: A model of brain tissue damage in Streptococcus pneumoniae meningitis

Hippocampal slices of newborn rats were exposed to either heat-inactivated Streptococcus pneumoniae R6 (hiR6) equivalent to 10(6) and 10(8) CFU/ml, lipoteichoic acid (LTA) (0.3 mug/ml and 30 mug/ml), peptidoglycans (PG) (0.3, 30, 50 and 100 mug/ml), pneumococcal DNA (pDNA) (0.3 and 30 mug/ml) or medium only (control). Cell injury was examined by Nissl staining, Annexin V and NeuN immunohistochemistry, and quantified by propidium iodide (PI) uptake and by determining neuron-specific enolase (NSE) concentration in the culture medium. Necrotic and apoptotic cell damage occurred in all treatment groups. Overall damage (Nissl and PI staining) was most prominent after hiR6 (10(8) CFU/ml), followed by LTA (30 mug/ml), pDNA (30 mug/ml), and not detectable after PG (30 mug/ml) exposure. PG (100 mug/ml) induced severe damage. Apoptotic cells were most frequent after exposure to LTA and hiR6. Damage in the neuronal cell layers (NeuN, NSE) was most severe after treatment with hiR6 (10(8) CFU/ml), followed by PG (100 mug/ml), pDNA (30 mug/ml), and LTA (30 mug/ml). (C) 2001 Elsevier Science B.V. All rights reserved.