In recent years, there are an increasing number of proteomics studies that investigated the alterations in the
protein expression relevant to human diseases but none for
stroke. We, therefore, attempted such a study in a paradigm of focal
cerebral ischemia in rat. Rats were subjected to
cerebral ischemia by unilateral occlusion of the middle cerebral artery. Global
protein analysis was performed after 24h on the lesioned and
sham-control cerebral cortex using two-dimensional gel electrophoresis.
Protein spots with more than a 3-fold change in intensity were identified by mass spectrometry.
Middle cerebral artery occlusion (MCAO) caused
infarct volume of 18-22% predominantly in the cortex of the lesioned hemisphere. Two-dimensional gel electrophoresis resolved about 1500
protein spots of which only 12 were significantly upregulated by 3-46-fold. Three spots were identified to be
dihydropyrimidinase-related protein 2 (DRP-2, also known as
collapsin response mediator
protein 2 (CRMP-2) or turned on after division, 64 kD
protein (TOAD-64)). The spots varied in pI values only and this may reflect different phosphorylation status of the same
protein. Two spots were identified as
spectrin alpha II chain (rat fragment, also known as
alpha-fodrin or non-erythroid alpha chain, SPNA-2); and one spot each for heat shock cognate
protein 70 pseudogene 1 (HSC70-ps1, also known as
heat shock protein 8 pseudogene 1), and
tropomodulin 2 (Tmod2). The upregulation of
protein expression was corroborated by observed upregulation of
mRNA expression. The remaining five spots were not identified satisfactorily. As DRP-2,
spectrin, and Tmod2 are involved in axonal and neurite growth as well as synaptic plasticity and maturation, the presently observed upregulation of the expression of these
proteins may indicate active neuroregeneration and repair at 24h after the induction of
cerebral ischemia.