Effect of fish oil
supplementation in a rat model of multiple mild traumatic brain injuries

T., Van KC., Gavitt BJ., Grayson K., Lu Y., Lyeth BG., Pichakron KO.  Restorative Neurology and Neuroscience. 2013; ahead
of print

Take Home Message: Pre-injury supplementation with
omega-3-fatty acids may improve cognitive and physiologic recovery following
brain injury.

Repetitive mild traumatic brain
injuries (MTBI) may lead to irreversible brain damage due to the secondary
effects that follow an MTBI (i.e.,
oxidativedamage). Omega-3- fatty acids, DHA and EPA, have been
show to reduce the secondary effects of an MTBI by reducing oxidative damage. Given
the frequency and potential long term effects of repetitive MTBIs it is
imperative to find ways to prevent and treat the cumulative effects of an MTBI.
Therefore, the purpose of this study was to determine if a diet rich in omega-3
fatty acids would reduce cognitive deficits and neuronal cell death in a
fluid-percussion rat model of repetitive MTBI. Twenty-five rats completed the full experiment. Seven rats
were excluded due to a bad reaction to the fluid percussion injury or excessive
weight loss following the injury. Rat chows were custom made, with the first having
an additional 6% fish oil (8-10 g EPA and 8 g DHA;
Brevoortia Tyrannus, an Atlantic menhaden fish) and the other having an
addition 6% soybean oil (control diet). Both chows had the same calorie count,
essential nutrients, and oil content. Rats were randomly assigned to either
diet, and were given free access to their respective chow for 4 weeks
pre-injury and 2 weeks post injury. After 4 weeks the rats were subjected to a
bilateral MTBI via
fluid percussion to
create a MTBI. After 24 hours a second fluid percussion injury was administered
to generate a repeat MTBI. Cognitive evaluation was assessed for 5 consecutive
days (days 10-14) via the
Morris Water Maze.
Following the final cognitive trial the rats were euthanized and the brains
were examined for histological differences within the
CA2-3 hippocampal regions
(neurons imperative for memory and spatial navigation)
. The fish oil group was able to find the hidden platform and
spent more time within the target quadrant on day 14 post MTBI compared to the
soybean oil group. There were no differences observed within days 10-13. There
were no differences between the right and left hemispheres in the quantity of
surviving CA2-3 neurons; however, there was a trend for the fish oil group to
have a greater number of total CA2-3 neurons compared to control diet group.

This is an interesting study that mimicked
a repetitive blow to the head that would result in a MTBI. The rats that were
given the fish oil chow displayed better terminal cognitive performances within
the Morris Water Maze tests by exhibiting greater spatial memory retention than
their soybean oil counterparts. The histology demonstrated a trend for those on
the fish oil diet to have a greater number of surviving CA2-3 hippocampal
neurons. This data suggests that pre-injury supplementation with omega-3-fatty
acids may have the potential to improve the cognitive outcome after sustaining
multiple MTBIs. This study also suggests that many of the cognitive problems
following a concussive event may be due to the secondary effects of the
oxidative stress on the tissue, which may be alleviated by fish oil
supplementation; however, there was not an injury-free control group for comparison.
The fish oil supplementation may offset a variety of the neurometabolic events
that occur following a MTBI that helps to preserve or repair cognitive function
following injury. Further research is necessary to determine the duration and
dose of fish oil to receive benefits. Additionally, it should be distinguished
if omega-3-fatty acids from natural food source produce better or similar
neuronal protection results compared to supplementation.

Questions for Discussion: Do you think that taking fish oil
will help prevent long-term cumulative effects of repetitive brain injury? Have
you suggested this for your athletes?

Written by: Jane McDevitt PhD, ATC,
Reviewed by: Stephen Thomas


Wang T, Van KC, Gavitt BJ, Grayson JK, Lu YC, Lyeth BG, & Pichakron KO (2013). Effect of fish oil supplementation in a rat model of multiple mild traumatic brain injuries. Restorative Neurology and Neuroscience PMID: 23835930