Postmortem stability of enzymes detoxifying peroxide in brain

Area of Science:

• Biochemistry
• Forensic Science
• Neuroscience

Background:

• Enzyme activity in postmortem tissues is crucial for forensic analysis.
• Understanding the stability of key enzymes like glutathione peroxidase, glutathione reductase, and catalase is vital for accurate postmortem interval estimation.
• Cadaver cooling rates can influence biochemical markers.

Purpose of the Study:

• To determine the stability of glutathione peroxidase, glutathione reductase, and catalase activities in mouse brains postmortem.
• To assess the impact of simulated human cadaver cooling on these enzyme activities.
• To evaluate the effect of erythrocyte contamination on measured brain enzyme activities.

Main Methods:

• Mouse brains were stored at temperatures simulating human cadaver cooling for up to 48 hours.
• Activities of glutathione peroxidase, glutathione reductase, and catalase were measured at various time points.
• Brains were perfused with saline to assess the impact of potential erythrocyte contamination.

Main Results:

• Glutathione peroxidase activity remained stable for 48 hours postmortem.
• Catalase activity was stable for 24 hours, then decreased by 20%.
• Glutathione reductase activity decreased significantly after 4 hours, reaching 55% of initial levels by 48 hours.
• Saline perfusion did not affect enzyme activities, indicating minimal impact from erythrocyte contamination.

Conclusions:

• Glutathione peroxidase is a reliable marker for moderate postmortem delays.
• Catalase activity is stable for 24 hours but may be affected by longer delays.
• Glutathione reductase is unstable postmortem, requiring careful control matching for accurate measurements.
• These findings have implications for using enzyme activities in forensic investigations and determining postmortem intervals.