Meeting Abstract
For several decades, measuring plasma corticosterone levels has been a staple in studying the stress response. More recently, additional downstream metrics such as DNA damage have been studied using blood samples of animals with nucleated erythrocytes, such as house sparrows (Passer domesticus). However, the biological relevance of blood DNA damage is unknown; baseline levels of DNA damage across multiple tissue types must first be established in order for this method to be further validated. We assessed the background levels of DNA damage in the blood, abdominal fat, hippocampus, hypothalamus, and the liver in house sparrows in three life-history stages: captive adult, wild-caught adult, and wild-caught juvenile house sparrows. The tissues studied play different roles in the stress response and health of the individual, suggesting they could be differentially affected by stress. The use of captive and wild-caught adults as well as juveniles allows for the effects of captivity and life-history to be controlled for. Tissues were collected upon capture and comet assays were used to measure DNA damage. The damage for each tissue was averaged across the individuals of the experimental groups, and the data mostly supports the hypothesis that unstressed individuals have low levels of DNA damage and low variation across tissues, with the exception of: elevated average blood tissue damage in juveniles, decreased hypothalamus damage in captive adults, and elevated hippocampus damage in captive adults. We hope these data will help further the understanding of DNA damage as a metric for stress and the overall physiology of the stress response.
