Traumatic brain injury (TBI) in children less than 8 years of age leads to decline in intelligence and executive functioning. Neurological outcomes after TBI correlate to development of
cerebral edema, which affect survival rates after TBI. It has been shown that
myosin light-chain kinase (MLCK) increases
cerebral edema and that pretreatment with an MLCK inhibitor (ML-7) reduces
cerebral edema. The aim of this study was to determine whether inhibition of MLCK after TBI in postnatal day 24 (PND-24) mice would prevent breakdown of the blood-brain barrier (BBB) and development of
cerebral edema and improve neurological outcome. We used a
closed head injury model of TBI.
ML-7 or saline treatment was administered at 4 h and every 24 h until sacrifice or 5 days after TBI. Mice were sacrificed at 24 h, 48 h, and 72 h and 7 days after impact. Mice treated with
ML-7 after TBI had decreased levels of MLCK-expressing cells (20.7±4.8 vs. 149.3±40.6), less
albumin extravasation (28.3±11.2 vs. 116.2±60.7 mm(2)) into surrounding parenchymal tissue, less
Evans Blue extravasation (339±314 vs. 4017±560 ng/g), and showed a significant difference in wet/dry weight ratio (1.9±0.07 vs. 2.2±0.05 g), compared to saline-treated groups. Treatment with
ML-7 also resulted in preserved neurological function measured by the wire hang test (57 vs. 21 sec) and two-object novel recognition test (old vs. new, 10.5 touches). We concluded that inhibition of MLCK reduces
cerebral edema and preserves neurological function in PND-24 mice.