动物实验 z-bo 2020-11-05 337

　　Most people can gradually recover from trauma, but a small number of people suffer from post-traumatic stress disorder (PTSD)-an extreme reaction to severe trauma (such as war, car accident, natural disaster). Scientists have been searching for the biological basis of the disease.

　　The researchers exposed about 100 experimental mice to the messy cat litter environment-making them worried about the presence of predators, and tested the impact of trauma on the experimental mice a week later. Approximately one-quarter of the experimental rats were classified as "extreme" responders, that is, they showed extremely high levels of anxiety and easily heard high-decibel noise. Another quarter of the experimental mice are the "minimal" responders, that is, the level of anxiety displayed is the same as that of the experimental mice in a normal environment.

　　In order to explore the mechanisms that control trauma sensitivity, the researchers used DNA microarray technology to scan 22,000 genes in samples from blood, amygdala, and hippocampus (a brain region related to fear and memory). Among them, 86 to 334 genes showed changes in expression levels-this seems to be related to the maximum or minimum response ability.

　　Most genes seem to express fragility or resilience, but they do not express both abilities at the same time. Daskalakis, a neuroendocrinologist at Icahn School of Medicine at Mount Sinai in New York City, said the results show that at the genetic level, two different stress response systems seem to control an individual’s sensitivity to PTSD.

　　On the basis of this study, the researchers further speculated that 73 transcription factors control the expression of genes related to trauma vulnerability and resilience, of which 1/4 are related to glucocorticoid receptor signals. Scientists have long suspected that the occurrence of PTSD is related to the misregulation of glucocorticoid receptor signaling. Some studies have also shown that abnormally low levels of receptor activity may be the culprit.