Date of this Version
Neuroscience Letters 552 (2013) 87– 91
Glial fibrillary acidic protein (GFAP), a protein enriched in astrocytes, and Tau, a protein abundant inneuronal microtubules, are being widely studied as biomarkers of brain injury, and persistent severity-dependent increases in brain and blood have been reported. Studies on the acute changes of these proteinsafter blast exposure are limited. Using a mouse model of closely-coupled repeated blast exposures, wehave evaluated acute changes in the levels of GFAP and total Tau by Western blotting. Brain levels of GFAPand Tau proteins decreased significantly at 6 h and increased considerably at 24 h after repeated blastexposures. Plasma samples showed a similar initial decrease and later increase over this timeframe. Thisbiphasic pattern points to possible absorption or sequestration of these proteins from plasma immedi-ately after repeated blast exposures. Liver and spleen tissue showed significant increases in the levelsof GFAP and Tau protein at 6 and 24 h post-blast exposures whereas semi-quantitative RT-PCR analysisof liver showed no significant changes in the levels of GFAP or Tau mRNAs. These results suggest thatblast exposure causes transient changes in cell membrane integrity in multiple organs leading to abnor-mal migration of proteins from the tissues to the plasma and vice versa. This transient changes in cellmembrane permeability and subsequent bidirectional movement of molecules may contribute to thepathophysiology of TBI and polytrauma after blast exposure.