In the first stage, an initial screening of lncRNAs was conducted. Four rats were randomly assigned to two groups: one group at 0 hours and another at 24 hours, with two rats in each group. Myocardial tissue was collected at the time of death due to hemorrhagic shock and 24 hours post-mortem, respectively. The sequencing results were analyzed to identify candidate lncRNAs with time-dependent expression.
In the second stage, data were collected for model development. Twenty-one rats were randomly divided into groups corresponding to post-mortem intervals of 0, 1, 3, 6, 12, 18, and 24 hours, with three rats per time point. Myocardial tissue collection followed the experimental protocol outlined above. For each rat in every experimental group, RNA was extracted and reverse-transcribed into cDNA, and PCR was performed. Each sample was subjected to three technical replicates. Based on the collected experimental data, a mathematical model was developed.
In the third stage, the developed model was validated. Additional myocardial tissue samples were collected from nine rats at 9, 15, and 21 hours post-mortem, with three rats per time point. For each rat in every experimental group, RNA was extracted and reverse-transcribed into cDNA, and PCR was performed. Each sample was subjected to three technical replicates. These data were used for model validation. RNA extraction was followed by RT-qPCR experiments, and the resulting experimental data were incorporated into the existing mathematical model to assess its validity.