Age-at-injury influences the glial response to traumatic brain injury in the cortex of male juvenile rats

Glia influence neuronal development and aging. Few translational studies have examined how age at injury affects the glial response to traumatic brain injury (TBI). We hypothesized that rats injured before sexual maturity would exhibit a greater glial response, that persists into early adulthood, compared to rats injured near the onset of sexual maturity.

Postnatal day (PND)17 and PND35 rats received midline fluid percussion injury or sham surgery. In three cortical regions (peri-injury, S1BF, perirhinal), we investigated the glial response relative to age at injury, time post-injury (2H, 1D 7D, 25D, and 43D), and post-natal age, such that rats injured at PND17 or PND35 were compared at the same post-natal-age (e.g., PND17+25d post-injury=PND42; PND35+7d post-injury=PND42). We measured Iba1+ microglia cells and quantified their activation status. GFAP expression was examined using immunohistochemistry. Data were analyzed using Bayesian multivariate multi-level models.

Independent ...