Figure 2

Apoptosis in the rat hippocampal dentate gyrus after infection with S . pneumoniae . A: Histomorphological analysis show neurons forming apoptotic bodies (arrowhead), a morphological feature characterisitc for programmed cell death and evenly distributed over the lower and upper blade of the hippocampal dentate gyrus (Cresyl violet, original magnification 20× and 40× (insert)). B: The mean score of apoptotic cells (represented by the horizontal lines) in the vitamin B6-treated group is significantly smaller than the score of placebo-treated rats (unpaired t test, p > 0.02). C: Hippocampal NAD+ levels were measured at 3 different time points after infection. The amount of NAD+ in placebo-treated rats (solid circles; vertical bars show standard deviation) gradually decreases over time as an index of depletion of cellular energy stores in the hippocampus of infected rats. In contrast, the NAD+ level of rats treated with vitamin B6 (bare circles) rises from the time of infection to 24 h post-infection. Statistical analysis was performed using GraphPad Prism 4 (GraphPad Software, San Diego California, USA).