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How to judge the death of pig brain

How to judge the death of pig brain

4hw.com.cn: usually, doctors have many criteria to judge whether patients die. Recently, scientists found that the recovery of brain circulation after pig brain death has aroused heated debate. Let's see the details below.

How to define death more scientifically? Is there really 'immortality'? This is a long-standing proposition of mankind. The British journal Nature published a heavy neuroscience study on the 17th: American scientists reported a system that can restore the brain circulation and some cell functions of pigs several hours after brain death, but there is no evidence that there are whole brain electrical activities related to consciousness, cognition or other higher-order brain functions. This achievement is considered to have raised ethical disputes in the field and strongly questioned the hypothesis of how to define whether animals or humans survive.

Mammalian brain is extremely sensitive to the decline of oxygen supply level. Short-term interruption of blood flow can cause rapid consumption of oxygen and energy storage, which is believed to cause neuronal death and irreparable brain damage. Some studies have raised questions: is this damage cascade inevitable in a short time after blood flow interruption?

This time, the Yale School of medicine team assumed that even after a few hours of death, specific cell functions might be partially restored. To test this, they developed the brainex system, which simulates pulsatile blood flow (perfusion) at normal body temperature (37 ℃). In the study, 32 pig brains from food processing plants were connected to the brainex system hours after death. The team found that during the 6-hour perfusion period, cell death decreased and some cell functions (including synaptic activity) were restored. However, no evidence of whole brain network activity or whole brain function was found during the experiment.

This indicates that the cell recovery function of the brain is stronger than previously expected, and the degradation of cell function after blood flow interruption may be a slow process. However, it is still unknown whether it is possible to restore all normal brain functions with the help of brainex system.

Two review articles are attached to nature to discuss the significance of the study. In one, scientists at Case Western Reserve University School of medicine believe that the study may intensify the debate about human organ transplantation.

In another review, Duke University scientists pointed out that the possibilities opened by the study highlighted 'the potential limitations of current regulatory regulations on research animals'. They called for guidelines to help researchers deal with the ethical dilemmas caused by this study. The results also "questioned the long-standing hypothesis about how to determine whether animals or humans survive".

This method will also provide a platform to study the complete brain, and further tests are needed to explore its wider application.