Objective      To detect the expression of matrix metalloproteinase-9 (MMP-9) in the epileptic cortex from adult patients with intractable temporal lobe epilepsy (TLE) and to explore the potential role of MMP-9 in intractable epilepsy.       Methods      Twenty-four samples of temporal cortices from intractable TLE and fifteen cases of non-epileptic normal brain tissues were collected. The expression of MMP-9 in the samples was examined by RT-PCR

gelatin zymography and immunohistochemistry.       Results      The mRNA level and activity of MMP-9 were significantly higher in the epileptic cortices than in the control cortices (CTX) (P0.05). The immunohistochemical results showed that MMP-9 was weakly or moderately expressed in neurons and occasionally expressed in glial cells in the CTX. However

strong expression of MMP-9 was observed in pyramidal neurons and astrocytes in the epileptic cortices. The intensity of immunostaining was significantly higher in the epileptic cortices than in the CTX (intensity score: 2.13±0.56 vs 1.52±0.69; ratio of mean optical density: 55.60±7.20 vs 37.10±8.70; P0.05).       Conclusion      The increased expression of MMP-9 in temporal epileptic cortex might be closely involved in the pathogenesis of intractable epilepsy

suggesting that MMP-9 might be a new potential drug target for intractable epilepsy treatment.