Inflammation increases the development of depression behaviors in male rats after spinal cord injury. Academic Article uri icon


  • Following spinal cord injury, 18-26% of patients are diagnosed with depressive disorders, compared to 8-12% in the general population. As increased inflammation strongly correlates with depression in both animal and human studies, we hypothesized that the immune activation inherent to SCI could increase depression-like behavior. Thus, we proposed that reducing immune activation with minocycline, a microglial inhibitor, would decrease depression-like behavior following injury. Male Sprague-Dawley rats were given minocycline in their drinking water for 14 days following a moderate, mid-thoracic (T12) spinal contusion. An array of depression-like behaviors (social activity, sucrose preference, forced swim, open field activity) were examined prior to injury as well as on days 9-10, 19-20, and 29-30 post-injury. Peripheral cytokine levels were analyzed in serum collected prior to injury and 10 days post-injury. Hierarchical cluster analysis divided subjects into two groups based on behavior: depressed and not-depressed. Depressed subjects displayed lower levels of open field activity and social interaction relative to their not-depressed counterparts. Depressed subjects also showed significantly greater expression of pro-inflammatory cytokines both before and after injury and displayed lower levels of hippocampal neurogenesis than not-depressed subjects. Intriguingly, subjects who later showed depressive behaviors had higher baseline levels of the pro-inflammatory cytokine IL-6, which persisted throughout the duration of the experiment. Minocycline, however, did not affect serum cytokine levels and did not block the development of depression; equal numbers of minocycline versus vehicle-treated subjects appeared in both phenotypic groups. Despite this, these data overall suggest that molecular correlates of inflammation prior to injury could predict the development of depression after a physical stressor.

published proceedings

  • Brain Behav Immun Health

altmetric score

  • 4.35

author list (cited authors)

  • Brakel, K., Aceves, M., Garza, A., Yoo, C., Escobedo, G., Panchani, N., Shapiro, L., & Hook, M.

citation count

  • 11

complete list of authors

  • Brakel, Kiralyn||Aceves, Miriam||Garza, Aryana||Yoo, Chaeyoung||Escobedo, Gabriel||Panchani, Nishah||Shapiro, Lee||Hook, Michelle

publication date

  • January 2021