Meeting Abstract
Skin is an important physical barrier against pathogens, but it can become damaged through fighting with conspecifics, predator attacks, and assaults by biting insects. Therefore, the ability to quickly and effectively heal wounds directly impacts an animal’s health. The hormone corticosterone (CORT) has many complex effects on immune function and can slow wound healing. It has been suggested that CORT’s role during wound healing may be to act as a “brake” on inflammation and cell proliferation. This project aimed to clarify the role of CORT in the healing process by quantifying glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) in the skin of wounded (n=9) or unwounded (n=8) house sparrows (Passer domesticus) using radioligand binding assays. We also quantified receptors in three other tissues, and several different blood chemistry parameters using a VetScan machine. One day after wounding, plasma glucose was higher, and aspartate aminotransferase lower, in wounded birds compared to controls, which may be related to animals’ changing metabolic needs in response to tissue regrowth or the immune challenge of wounding. Birds had significantly decreased MR, but not GR, in the skin on their wounded leg compared to the skin on their unwounded leg. There was also a trend towards lower MR in wounded skin compared to unwounded birds. Receptors in three other tissues (liver, spleen and pectoralis muscle) did not differ between groups. This study suggests that decreasing the skin’s sensitivity to CORT immediately after wounding may be a necessary part of the normal healing process in wild birds.
