DNA brain damage after stress in rats.

OBJECTIVE

The purpose of this study was to verify the presence of DNA brain lesion after acute stress in rats.

METHOD

Adult male Wistar rats were divided into 3 groups according to the stressor (control, forced swimming or restraint), and sampled at 2 time points: immediately or 1week after stress. Trunk blood and the brain areas (prefrontal cortex, amygdala and hippocampus) were extracted for DNA analysis by the comet assay. The cells were classified according to the damage index and damage frequency based on the comet tail size.

RESULTS

Immediately after the stress, DNA damage was detected in the amygdala area and in the hippocampus after restraint and forced swimming. In the prefrontal cortex, DNA was damaged after forced swimming. However, no alteration was seen in blood. Seven days after the stress, DNA damage was still identified in the hippocampus after forced swimming and restraint, whereas no alteration was detected in the other brain areas or in blood.

CONCLUSION

One week after a single stressful event, a reversible DNA damage was identified in the prefrontal cortex and in the amygdala, whereas DNA damage in the hippocampus still remained.