Dynamic expression of adenylate kinase 2 in the hippocampus of pilocarpine model rats.

Studies have shown that adenylate kinase 2 (AK2) is released from the mitochondrial inner membrane space during neuronal apoptosis, which plays an important role in temporal lobe epilepsy (TLE). We investigated the expression of AK2 in the hippocampus of a pilocarpine model rats. Using reverse transcription polymerase chain reaction and immunohistochemistry, AK2 mRNA and immune-positive cells were investigated during the entire epileptic process in pilocarpine-induced rat model of TLE. AK2 mRNA level was increased in rat hippocampus during different phases of the epileptogenesis, and reached a peak at 72 h. At 72 h time point, AK2 mRNA level was more than threefold comparing with the control. AK2-positive cells were observed in all regions of the hippocampus in model rats, but not in brain tissues of controls. The mean percentage of AK2-positive cells was increased as early as 6 h following seizure and reached a peak at 72 h. The pattern of AK2 expression over time was similar to that observed during neuronal apoptosis as detected with TUNEL staining. These results suggest that AK2 participates in the pathophysiological process of TLE and may be a marker for neuronal apoptosis induced by pathological injury in TLE.