OBJECTIVE: This study aims to evaluate ALA-1.0, a blood-brain barrier permeable calpain-inhibitor as a potential traumatic brain injury (TBI) therapeutic in a rat model of TBI.
BACKGROUND: TBI afflicts people of all ages with over 1.7 million TBIs occurring per year. An effective treatment for TBI has not been determined. Calpain over-activation is a major contributor to aberrant cell function and neurodegeneration in secondary injury post-TBI. Therefore, calpain inhibition is a practical therapeutic strategy. ALA-1.0 is a novel calpain-inhibitor composed of the active inhibitor of the calpain protease inhibitor, leupeptin (leucyl-argininal), linked to the anti-epileptic drug, pregabalin, as a carrier molecule. This formulation permits the entire compound to cross the blood-brain barrier and target the site of neural injury after peripheral administration.
METHODS: A single 80 mg/kg dose of ALA-1.0 was administered intraperitoneally (i.p) immediately following moderate injury induced by the controlled cortical impact (CCI) rodent model of TBI. Control rats received the same moderate CCI injury, but were given saline i.p immediately following injury. Immunohistochemistry was performed at 48 hours post-TBI. Motor and behavioral analyses were conducted to evaluate the functional effects of ALA-1.0 administration post-TBI. Microglia and astrocyte activation were analyzed via immunohistochemistry at 3 weeks post-injury.
RESULTS: Rats given ALA-1.0 displayed a significant reduction in the number of degenerating cortical neurons in comparison to controls, as shown via Fluoro-Jade B staining (p<0.05). Western blot analysis showed protection of calpain-targeted cytoskeletal proteins αII-spectrin and microtubule-associated protein (MAP-2) in injured rats given ALA-1.0 (p<0.05).
CONCLUSIONS: A single dose of ALA-1.0 administered peripherally immediately after CCI injury is able to cross the blood-brain barrier and reach the injury site to decrease neurodegeneration through the inhibition of calpain. Disclosure: Dr. Dugue has nothing to disclose. Dr. Serrano has nothing to disclose. Dr. Hassen has nothing to disclose. Dr. Michelson has nothing to disclose. Dr. Shulman has nothing to disclose. Dr. Goodman has nothing to disclose. Dr. Ling has nothing to disclose.