Research Reports - Effects of traumatic brain injury on intestinal contractility
Neurogastroenterol Motil. 2013 Jul;25(7):593-e463
Olsen AB, Hetz RA, Xue H, Aroom KR, Bhattarai D, Johnson E, Bedi S, Cox CS Jr, Uray K
BACKGROUND: Patients with traumatic brain injury (TBI) often suffer from
gastrointestinal dysfunction including intolerance to enteral feedings. However,
it is unclear how TBI affects small intestinal contractile activity. The purpose
of this study was to determine if TBI affects intestinal smooth muscle function.
METHODS: Sprague-Dawley rats were subjected to controlled cortical impact injury
(TBI). Sham animals underwent a similar surgery but no injury (SHAM). Animals
were sacrificed 1, 3, and 7 days after TBI and intestinal smooth muscle tissue
was collected for measurement of contractile activity and transit, NF-kB
activity, and cytokine levels. Brains were collected after sacrifice to determine
volume loss due to injury.
KEY RESULTS: Contractile activity decreased significantly in ileum, but not
jejunum, in the TBI group 7 days after injury compared with SHAM. Brain volume
loss increased significantly 7 days after injury compared with 3 days and
correlated significantly with the contractile activity 1 day after injury. In the
intestinal smooth muscle, NF-kB activity increased significantly in the TBI group
3 and 7 days after injury vs SHAM. Wet to dry weight ratio, indicating edema,
also increased significantly in the TBI group. Interleukin-1α, -1β, and -17
increased significantly in the TBI group compared with SHAM.
CONCLUSIONS & INFERENCES: Traumatic brain injury causes a delayed but significant
decrease in intestinal contractile activity in the ileum leading to delayed
transit. The decreased intestinal contractile activity is attributed to secondary
inflammatory injury as evidenced by increased NF-kB activity, increased edema,
and increased inflammatory cytokines in the intestinal smooth muscle.