Correlation of CCL2 mRNA changes in piglet cerebral cortex 24 hours after cortical impact. Expressions of mRNA were normalized to GAPDH mRNA and expressed as mean fold change relative to mRNA expressed in contralateral tissue from the same piglet. (A) In the penumbra, changes in CCL2 mRNA were independent to changes in PTGS2 mRNA. (B) CCL2 mRNA changes in the penumbra correlated to CCL2 mRNA changes in the lesion core. CCL2, chemokine ligand 2.