3
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Wound-healing ability is conserved during periods of chronic stress and costly life history events in a wild-caught bird.

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Chronic stress, potentially through the actions of corticosterone, is thought to directly impair the function of immune cells. However, chronic stress may also have an indirect effect by influencing allocation of energy, ultimately shifting resources away from the immune system. If so, the effects of chronic stress on immune responses may be greater during energetically-costly life history events. To test whether the effects of chronic stress on immune responses differ during expensive life history events we measured wound healing rate in molting and non-molting European starlings (Sturnus vulgaris) exposed to control or chronic stress conditions. To determine whether corticosterone correlated with wound healing rates before starting chronic stress, we measured baseline and stress-induced corticosterone and two estimates of corticosterone release and regulation, negative feedback (using dexamethasone injection), and maximal capacity of the adrenals to secrete corticosterone (using adrenocorticotropin hormone [ACTH] injection). After 8days of exposure to chronic stress, we wounded both control and chronically stressed birds and monitored healing daily. We monitored nighttime heart rate, which strongly correlates with energy expenditure, and body mass throughout the study. Measures of corticosterone did not differ with molt status. Contrary to work on lizards and small mammals, all birds, regardless of stress or molt status, fully-healed wounds at similar rates. Although chronic stress did not influence healing rates, individuals with low baseline corticosterone or strong negative feedback had faster healing rates than individuals with high baseline corticosterone or weak negative feedback. In addition, wound healing does appear to be linked to energy expenditure and body mass. Non-molting, chronically stressed birds decreased nighttime heart rate during healing, but this pattern did not exist in molting birds. Additionally, birds of heavier body mass at the start of the experiment healed wounds more rapidly than lighter birds. Finally, chronically stressed birds lost body mass at the start of chronic stress, but after wounding all birds regardless of stress or molt status started gaining weight, which continued for the remainder of the study. Increased body mass could suggest compensatory feeding to offset energetic or resource demands (e.g., proteins) of wound healing. Although chronic stress did not inhibit healing, our data suggest that corticosterone may play an important role in mediating healing processes and that molt could influence energy saving tactics during periods of chronic stress. Although the experiment was designed to test allostasis, interpretation of data through reactive scope appears to be a better fit.

          Related collections

          Author and article information

          Journal
          Gen. Comp. Endocrinol.
          General and comparative endocrinology
          Elsevier BV
          1095-6840
          0016-6480
          April 01 2016
          : 229
          Affiliations
          [1 ] Department of Biology, Tufts University, Medford, MA 02155, United States; Department of Zoology, Oklahoma State University, Stillwater, OK 74078, United States. Electronic address: sarah.durant@okstate.edu.
          [2 ] Department of Biology, Tufts University, Medford, MA 02155, United States.
          Article
          S0016-6480(16)30053-3
          10.1016/j.ygcen.2016.03.009
          26965949
          dd111323-1083-4fff-9a6d-9b63a0d5de95
          History

          Energy expenditure,Heart rate,Molt,Negative feedback,Reactive scope,Allostasis,Corticosterone

          Comments

          Comment on this article