The present work designed to estimate postmortem expression of mRNA of certain hepatic genes in rats in the presence or absence of postmortem heat stress using qRT-PCR technique in correlation to postmortem interval (PMI). Rats were sacrificed and divided into, control group (PMI=0 h), room temperature and heat stressed (41⁰C) groups. In control group, liver samples were collected immediately after death, while in the second and third groups, samples were collected at 1, 3 and 6 hours postmortem. The results showed significant reductions in pro-inflammatory gene transcripts (TNFα and IL-1β) at all-time points compared to control group with an inhibitory effect of postmortem heat stress on expression of TNFα at 1 and 6 h after death. Whereas postmortem expression of genes encode apoptosis was significantly increased at 3 and 6 h postmortem compared to control group. Postmortem heat stress reduced the hepatic expression of Bcl-2 and Caspase-3 at 3 and 6 h of PMI and increased the expression of Caspase-3 at 1 h after death compared to room temperature group. Meanwhile, postmortem hepatic mRNA expression of c-fos was significantly induced after death at 3 and 6 h PMI. Postmortem heat stress significantly reduced c-fos expression at 3 and 6 h after death. Thanatotranscriptome of genes encode inflammation, apoptosis as well as c-fos varied in their correlations to PMI. Additionally, the results showed disparities in the effect of postmortem heat stress according to the studied gene and time.
Key words: Thanatotranscriptome, postmortem, heat stress, apoptosis, inflammation