Several factors may affect the quality of RNA and proteins, and DNA binding activities of transcription factors in postmortem human tissues. In the present study, the RNA quality was controlled and no samples with degraded RNA were used in the analysis. No degraded proteins seen as smearing or additional bands on western blots were evident in any sample. Using our protocol for fast extraction of nuclear proteins from frozen tissues, we observed similar levels of the NF-κB/p50 homodimer DNA binding activities in extracts of frozen human samples and of rat brain tissues prepared immediately after decapitation, thus demonstrating low if any inactivation of these factors in human samples. Six subjects demonstrated no NF-κB, p50 homodimer and Ku protein DNA binding activity were characterized by low brain pH values and were omitted from the analysis. Levels of RNA, proteins and NF-κB/p50 homodimer DNA-binding did not significantly correlate with postmortem interval and age at death of subjects analyzed suggesting that influences of these covariates on studied molecular parameters are negligible.
