Journal of neurotrauma
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Journal of neurotrauma · Oct 2009
Heat stress preconditioning improves cognitive outcome after diffuse axonal injury in rats.
This study investigates the influence of heat stress preconditioning on cognitive outcome for rats with diffuse axonal injury (DAI), and attempts to examine the underlying mechanisms. Wistar rats were divided into four groups: rats subjected to heat stress preconditioning 24 h before induction of DAI (n = 10; HSDAI group), a DAI alone group (n = 10), a heat stress alone group (n = 10), and a sham-injury group (n = 10). From day 14 post-injury, the rats' learning abilities and memory were tested using the Morris water maze (MWM) task, followed by long-term potentiation (LTP) recording of the hippocampus. ⋯ Following injury, retraction balls, shrunken neurons, and HSP70 expression were visible in the brains of rats from the DAI and HSDAI groups; recovery was expedited in the rats belonging to the HSDAI group, as these pathological changes were alleviated, coincident with higher expression of HSP70. The rats' abilities for learning and memory were impaired following DAI; this may be due to the disconnection of brain regions, damage to neurons in the hippocampus, and a decrease in synaptic plasticity. Heat stress preconditioning is able to significantly attenuate this cognitive impairment, possibly mediated by the neuroprotective effect of HSP70.