This study was done on 81 rats to evaluate the post mortem interval PMI depending on
expression of Gapdh mRNA and protein response to immunostaining.
Gapdh in liver demonstrated less stability &degradation with a significant decrease in
amplicon detection across the entire transcript after 48 hour PMI with no difference in
transcript level until 96 hours, and showed a strong significant positive correlation
between PMI and Gapdh expression (r = 0.837, p = 0.000).
Consistent and surprising robustness of Gapdh transcript levels in brain with non
significant low correlation between gene expression and PMI (r = 0.129, p = 0.522).
Gapdh showed less stability with significant decreases in transcript levels in liver with
increasing PMI (up to 48 hour). However, it shows low correlation between Gapdh
transcript and PMI in brain.
PCNA showed positive immunostaining in the hepatocytes cytoplasm and in the nuclei
in the first few hours after death (0-9hours), later on only few cells showed positive
immunostaing in both cytoplasm and nuclei (12hours). At 24-48 hours the hepatocytes
only showed positive cytoplasmic PCNA reaction, while in 72-96 hours the PCNA
immunostaining showed negative reaction.
In the brain at 0-12 hours positive PCNA was located in the cytoplasm and nuclei of
the nerve cells. At 24 hours only positive PCNA immunostaining was located in the
cytoplasm and negative reaction in the nuclei. At 48-96 negative PCNA
immunostaining was noticed.