Abstract W MP73: Protective Effect of Argatroban on Behavioral Outcome Following MCAo up to Four Hours
Background and Purpose: We showed previously that thrombin enters brain and causes damage to the neurovascular unit (NVU) during ischemia. We hypothesized that the direct thrombin inhibitor argatroban after MCAo would ameliorate behavioral deficits. We explored the therapeutic time window with a standard bioassay following pre-clinical testing guidelines from RIGOR and STAIR.
Methods: Male Sprague-Dawley rats underwent MCAo during which each received placebo, 18mg/kg Argatroban over 24 hours (hi dose), or 10mg/kg over 24 hours (lo dose). Blood flow was restored by removing the filament after variable times. At reflow and daily thereafter animals were rated using a modified Bederson scale. After 48 hours the animals were sacrificed and lesion volume measured with TTC imaging (planimetry; Image Pro Plus). Animals were assigned to treatment randomly and studies were triple blinded at surgery, at behavioral assessment, and during histology. We used the quantal bioassay (Exp Neurol 1997;147:346-352) to compute the ED50 for each group, which measures the duration of ischemia in minutes needed to cause abnormal behavior in 50% of the group.
Results: Both doses of argatroban were superior to saline when treatment was delayed as long as 3 hours. For example, after 1 hour delay, the ED50±SD for placebo (n=19) was 24.0±5.6, lo dose (n=19) 46.3±3.4, hi dose (n=19) 40.6±5.7 (p<0.05, t-test, Bonferroni). After 3 hours (Figure), placebo (n=25) was 15.5±3.3, lo dose (n=20) 30.1±5.6, and hi dose (n=20) 30.1±3.74 (P<0.05). After 4 hours delay, there were no beneficial effects. Lesion volumes measured by TTC confirmed the behavioral results.
Conclusion: Argatroban after MCAo significantly ameliorated behavioral deficits and reduced lesion volume compared to saline. The effect was robust and seen with 2 doses. Protection was noted after a delay as long as 3 hours but not 4 hours. These data support earlier findings that thrombin inhibition shows promise for neuroprotection.
Author Disclosures: L. Zhao: None. B. Pereira: None. J. Lamb: None. P. Rajput: None. P. Lyden: Research Grant; Significant; NINDS funded this research.
- © 2014 by American Heart Association, Inc.