Depression and wound healing are bidirectional processes for adults and children consistent with the conception of depression as systemic. This systemic interaction is similar to the “bidirectional impact of mood disorder on risk for development, progression, treatment, and outcomes of medical illness” generally. And, evidence is growing that the bidirectional impact of mood disorder may be true for injuries and for trauma surgery. Animal models have provided some support that treatment of depression may improve wound healing. An established biological model for a mechanism delaying wound healing is increased cortisol secretion secondary to depression and/or stress, and impaired immune response, in addition or together with the other factors such as genetic or epigenetic risk for depression. Cellular models relate both to wound healing and to depression include cytokines, the inflammatory response (Miller et al, 2008), and cellular aging (Telgenhoff and Shroot, 2005) reflected in shorter leukocyte telomere length (LTL) (Verhoeven et al, 2016). Another model of stress impacting wound healing investigated genetic correlates—immediate early gene expression or IEG from the medial prefrontal cortex, and locomotion, in isolation-reared juvenile rats. Levine et al (2008) compared isolation reared to group reared samples, and found that, immediate gene expression in the medial prefrontal cortex (mPFC) was reduced, and behavioral hyperactivity increased, in juvenile rats with 20% burn injuries. Wound healing in the isolation reared rats was significantly impaired. They concluded that these results provide candidates for behavioral biomarkers of isolation rearing during physical injury, i.e. reduced immediate mPFC gene expression and hyperactivity. They suggested that a biomarker such as IEGs might aid in demarcating patients with resilient and adaptive responses to physical illness from those with maladaptive responses
Isolation rearing impairs wound healing and is associated with increased locomotion and decreased immediate early gene expression in the medial prefrontal cortex of juvenile rats
