Traumatic brain injury (TBI) can cause damage to the brain and can have serious consequences on physical and neurological health. Repeated mild TBIs are a risk factor for developing the neurodegenerative disorder, chronic traumatic encephalopathy (CTE), which can lead to emotional, cognitive, and memory problems. Zinc, a molecule released in the brain under normal conditions, has been found to play a role in neurological processes. Following a TBI, increased zinc release can cause protein segments to become toxic neurofibrillary tangles, leading to neurodegeneration. However, subsequent zinc-deficient states in the brain promote cell-damaging molecules and cell death.
To explore the relationship between supplemental zinc and neurological recovery in CTE, a team of researchers conducted an animal study. Mice were given zinc supplementation prior to injury and observed after single and repeated TBIs. The researchers assessed behavioral changes and biological changes post-mortem with and without zinc supplementation. The results of the study showed that:
- Zinc supplementation improved times to normal ambulation (independent walking) on days four and five after injury.
- Zinc-supplemented mice regained ambulation as fast as non-injured mice, while mice without zinc supplementation experienced delays in ambulation.
- Zinc supplementation partially remediated the subsequent loss of zinc in the brain following TBI but did not completely restore zinc to pre-injury levels.
- While there were no significant effects of zinc supplementation in cognitive and behavioral outcomes, female subjects experienced delayed ambulation and increased anxiety compared to males.
These findings suggest that zinc supplementation may improve short-term outcomes involving physical and neurological recovery but may not be an adequate proactive therapy for chronic cognitive and behavioral consequences of TBI. Zinc supplementation shows a particularly active role in promoting ambulation, which may be an important clinical direction for future research regarding patient mobility following TBI. While further research is necessary to explore the biological relationship of zinc to the brain during TBI, clinical researchers should consider zinc as a potential factor in neurological recovery.
Neely C, Barkey R, Hernandez C, et al. Prophylactic zinc supplementation modulates hippocampal ionic zinc and partially remediates neurological recovery following repetitive mild head injury in mice. Behavioral Brain Research. (May 2022).