To elucidate the possible neuroprotective mechanisms of Tat-p27 against ischemia, the levels of oxidative products such as malondialdehyde (MDA) and 8-iso-prostaglandin F2α (8-iso-PGF2α) were measured 3 and 12 h after ischemia in the hippocampus. This evidence concerns the gene CDKN1B and ischemia.