A few hours after death, some brain genes are more active

Glial cells Image source: Kateryna_Kon

In the few hours after death, the gene expression of certain cells in the brain is still active, and even the activity increases.

Researchers at the University of Illinois in the United States analyzed the gene expression of fresh brain tissue-these brain tissues were collected from routine brain surgery.

These "zombie genes" (genes that increase in expression over a period of time after death) are specific: they come from glial cells.

"It is not surprising that glial cells will expand after death, because they are inflammatory cells and their task is to clean up after brain damage such as hypoxia or stroke.

"Most research assumes that when the heart stops beating, everything in the brain also stops, but that's not the case," Loeb said.

Initially, the Loeb team noticed that the overall pattern of gene expression in fresh human brain tissue did not match the published autopsy reports, which involved people with no neurological diseases or with multiple neurological diseases.

Loeb said: "We decided to conduct a simulated death experiment to observe the gene expression of a large piece of human brain tissue collected recently from 0 to 24 hours.

The researchers found that about 80% of the analyzed genes were relatively stable within 24 hours, with little change in expression.

Another group of genes that exist in neurons has been shown to have a complex relationship with human brain activities (such as memory, thinking, and seizures).

The third group of genes is the "zombie gene".

"This discovery does not mean that we should abandon human tissue research, it just means that researchers need to consider these genetic and cellular changes, and minimize the time between deaths to reduce the magnitude of these changes.

Related paper information: https://doi.