http://journals.lww.com/ccmjournal/Abstract/2012/12001/189___Acetyl_L_Carnitine__Alcar__Provides.156.aspx
Abstract
Introduction: Traumatic brain injury (TBI) is the leading
cause of morbidity in children and survivors suffer from long-term
cognitive and memory impairment. TBI is characterized by reduced aerobic
cerebral energy metabolism early after injury. Exogenous
acetyl-L-carnitine (ALCAR) is metabolized in the brain to acetyl
coenzyme A and then enters the tricarboxylic acicoenzyme Ad cycle. ALCAR is
neuroprotective in animal models of cerebral ischemia and spinal cord
injury, with limited studies in TBI.
Hypothesis: Treatment with ALCAR during the first 24 h following TBI in immature rats improves neurologic outcome.
Methods: Postnatal day 21-22 rats underwent baseline
MRI/MRS imaging, then were randomly assigned to sham surgery or
controlled cortical impact (CCI) to the left parietal cortex. At 1, 4,
12 and 23h after injury, rats received ALCAR (100 mg/kg,
intraperitoneally) or drug vehicle (normal saline). Longitudinal in vivo
T2 MRI and MRS imaging was performed at 2-4hr, 24hr, 72hr, 7days and 21
days after brain trauma to assess structural and biochemical integrity.
Functional recovery was assessed by battery of behavioral tests (beam
walking, novel object recognition, novel object location and
Morris-Water-Maze) up to 28d after TBI.
Results: TBI resulted in reduced time spent with a novel
object in vehicle-treated rats compared to shams at all time points
assessed (7days: 43.67 +/- 6.1% vs. 65.9 +/- 3.6%; 14days: 51.9 +/- 2.6%
vs. 66.12 +/- 3.77%; 21days: 41.9 +/- 4.2% vs. 65.4 +/- 5.29%; n=11).
TBI rats treated with ALCAR had improved time spent with a novel object
compared to vehicle-treated injured rats (7days: 57.97 +/- 7.6%; 14days:
62.6 +/- 2.98%; 21days: 61.7 +/- 5.8%; n = 11; p < 0.05 vs.
vehicle). ALCAR treated rats demonstrated improved latency to find the
hidden platform in Morris water maze. Hippocampal MRS experiments
revealed that ALCAR-treated immature rats had increased GABA and
glutamine in the first 24hr after TBI vs. vehicle-treated injured rats.
Conclusions: Treatment with ALCAR during the first 24 h
after TBI supported brain astrocytic and GABAergic neuronal metabolism
acutely and improved long-term (up to 28days) neurologic outcome.
Support: K08 NS 069815
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