Aim: To study the involvements of nuclear factor of activated T-cells (NFATc) and NF-kappaB in calcineurin-mediated ischemic brain damage in vivo.
Methods: The rat transient forebrain ischemia conducted through 15 min ischemia followed by 8, 24, and 72 h reperfusion was induced using the four-vessel method. The rats were divided randomly into five groups; sham control group, ischemia/reperfusion (I/R) group, CsA treated groups (for 8, 24, and 72 h reperfusion). Western blotting was performed to detect changes of FasL, NFATc, I-kappaB-alpha, and phospho-I-kappaB-alpha protein expression, and gel shift assays for NFAT FasL-DNA binding activities.
Results: Western blotting showed that the expressions of both FasL and NFATc protein were significantly increased in the hippocampus of rat subjected to transient forebrain ischemia in comparison with those of the sham control group, which were markedly reduced by CsA. The I-kappaB-alpha protein showed no changes in all groups, and phospho-I-kappaB-alpha protein was not observed in this study. Proximal and distal FasL promoter NFAT sites bind NFAT proteins from the hippocampal neurons subjected to transient forebrain ischemia, and DNA-binding activities increased significantly compared with those of the sham control group. CsA markedly inhibited these changes.
Conclusion: NFATc may be involved in calcineurin-mediated ischemic brain damage and transcription factor NF-kappaB may not be involved.