Introduction: One of the most essential duties in forensic medicine is determining the 
postmortem interval. Objectives: The study's purpose is to estimate time passed since death in 
relation to oxidative stress markers, histopathological changes, and prostatic specific antigen in 
the prostate. Methods: Fifty mature male albino rats were classified into 5 main groups. Rats 
were used for determining postmortem changes and oxidative stress markers at five different 
postmortem intervals (0, 1, 5, 10, 15 days) with prostatic specific antigen (PSA) 
immunohistochemistry in the prostate. Results: Prostatic gland oxidant parameters (MDA, NO) 
revealed a significant increase while its antioxidant parameters (GSH, SOD) showed a 
significant decrease with increased postmortem time. The prostate gland showed normal 
histology at 0 hours postmortem (PM). While, at 1 day, it revealed minimal autolysis (<5%). 
Starting from 5 days, moderate autolysis (10–50%) was seen. Ten to fifteen days, moderate to 
severe autolysis (≥50%) appeared in most of the samples. Staining for PSA showed high 
expression (++) at 0 hours PM. Moreover, a significant decrease in the amount of PSA's stained 
areas that revealed low expression (+) was detected at 1 and 5 days PM. Negative (−) or no 
immunoreactivity for PSA has been detected at 10 and 15 days PM. Conclusion: Prostatespecific antigen proved to be a useful parameter consistent with the histopathological changes 
for the estimation of postmortem interval from the prostate. It is approved that the derived 
oxidative stress markers equations can be helpful in detecting the postmortem interval in forensic 
science Received in original form: 21 September 2022 Accepted in a final form: 11December 2022