title: Pretreatment with calpain inhibitor CEP-4143 inhibits calpain I activation and cytoskeletal degradation, improves neurological function, and enhances axonal survival after traumatic spinal cord injury.
abstract: The pathophysiology of traumatic spinal cord injury (SCI) involves abnormal activation of the neutral cysteine protease calpain I (EC 3.4.22.17). In the present study we examined the effect of the calpain inhibitor CEP-4143 on cytoskeletal protection and neurological recovery after SCI in adult rats. Microinjection of 50 mM CEP-4143 into the T7 vertebral segment 10 min before a 35-g clip compression injury resulted in inhibition of calpain activation at 2 and 4 h postinjury, as determined by western blotting for calpain I-mediated spectrin degradation, and significantly attenuated the degradation of dephosphorylated NF200 neurofilament protein at 4 and 8 h postinjury. To examine the in vivo chronic neuroprotective effects of CEP-4143, animals underwent microinjection with saline or 50 mM CEP-4143 10 min before injury, followed by weekly blinded behavioral assessments for 6 weeks. Animals receiving CEP-4143 treatment showed significant improvement over saline-treated controls on the Basso Beattie Bresnahan locomotor rating scale (p < 0.02) and inclined plane test (p < 0.05). Counts of neurons in the red nucleus retrogradely labeled by fluoro-gold after introduction distal to the injury site were significantly higher in CEP-4143-treated animals. Finally, morphometric assessment of the injury site by computer-assisted image analysis revealed significant tissue preservation in CEP-4143-treated animals. We conclude that the calpain antagonist CEP-4143 exhibits biochemical, behavioral, and anatomical neuroprotection following traumatic SCI.
authors.affiliation: Division of Neurosurgery and Playfair Neuroscience Unit, Toronto Western Hospital, Ontario, Canada.
authors.forename: P A
authors.initials: PA
authors.lastname: Schumacher
authors.forename: R G
authors.initials: RG
authors.lastname: Siman
authors.forename: M G
authors.initials: MG
authors.lastname: Fehlings
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects / Q000378:metabolism*; D002154:Calpain / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002452:Cell Count; D003599:Cytoskeleton / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005456:Fluorescent Dyes; D008124:Locomotion; D008845:Microinjections; D016900:Neurofilament Proteins / Q000378:metabolism; D009474:Neurons / Q000201:enzymology / Q000648:ultrastructure; D018696:Neuroprotective Agents / Q000494:pharmacology; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000201:enzymology / Q000534:rehabilitation; D013266:Stilbamidines; D013379:Substrate Specificity
chemical_list: C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D016900:Neurofilament Proteins; D018696:Neuroprotective Agents; D013266:Stilbamidines; C051774:neurofilament protein H; D002154:Calpain