Expression of PTGS2 and CCL2 in the penumbra region of piglet cerebral cortex 24 hours after cortical impact. Messenger RNAs in the adjacent lesion core in the penumbra were expressed as mean fold change (±SEM) relative to mRNA abundance in cortical tissues from a similar region in the uninjured contralateral hemisphere. Target mRNAs were normalized to GAPDH mRNA as an endogenous control reference and differences among groups tested with Student’s t test. *Means ± SEM differ P < 0.05 relative to contralateral region (n = 6). CCL2, chemokine ligand 2; PTGS2, prostaglandin-endoperoxide synthase 2.