title: AAVshRNA-mediated suppression of PTEN in adult rats in combination with salmon fibrin administration enables regenerative growth of corticospinal axons and enhances recovery of voluntary motor function after cervical spinal cord injury.
abstract: Conditional genetic deletion of phosphatase and tensin homolog (PTEN) in the sensorimotor cortex of neonatal mice enables regeneration of corticospinal tract (CST) axons after spinal cord injury (SCI). The present study addresses three questions: (1) whether PTEN knockdown in adult rats by nongenetic techniques enables CST regeneration, (2) whether interventions to enable CST regeneration enhance recovery of voluntary motor function, and (3) whether delivery of salmon fibrin into the injury site further enhances CST regeneration and motor recovery. Adult rats were trained in a staircase-reaching task and then received either intracortical injections of AAVshPTEN to delete PTEN or a control vector expressing shRNA for luciferase (AAVshLuc). Rats then received cervical dorsal hemisection injuries and salmon fibrin was injected into the injury site in half the rats, yielding four groups (AAVshPTEN, AAVshLuc, AAVshPTEN + fibrin, and AAVshLuc + fibrin). Forepaw function was assessed for 10 weeks after injury and CST axons were traced by injecting biotin-conjugated dextran amine into the sensorimotor cortex. Rats that received AAVshPTEN alone did not exhibit improved motor function, whereas rats that received AAVshPTEN and salmon fibrin had significantly higher forelimb-reaching scores. Tract tracing revealed that CST axons extended farther caudally in the group that received AAVshPTEN and salmon fibrin versus other groups. There were no significant differences in lesion size between the groups. Together, these data suggest that the combination of PTEN deletion and salmon fibrin injection into the lesion can significantly improve voluntary motor function after SCI by enabling regenerative growth of CST axons.
authors: Reeve-Irvine Research Center, Department of Anatomy and Neurobiology, osteward@uci.edu glewando@uci.edu.
authors: Gail
authors: http://orcid.org/0000-0001-8784-3243
authors: G
authors: Lewandowski
authors: Reeve-Irvine Research Center, Department of Anatomy and Neurobiology, Department of Neurobiology and Behavior, and Department of Neurosurgery, University of California, Irvine, California 92697 osteward@uci.edu glewando@uci.edu.
authors: Oswald
authors: O
authors: Steward
mesh_terms: D000367:Age Factors; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D002574:Cervical Vertebrae; D000229:Dependovirus / Q000235:genetics; D005260:Female; D005337:Fibrin / Q000008:administration & dosage*; D007276:Injections, Intraventricular; D009416:Nerve Regeneration / Q000187:drug effects* / Q000235:genetics; D051059:PTEN Phosphohydrolase / Q000037:antagonists & inhibitors* / Q000172:deficiency; D011712:Pyramidal Tracts / Q000187:drug effects* / Q000502:physiology; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects / Q000235:genetics; D012474:Salmon; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D005337:Fibrin; D051059:PTEN Phosphohydrolase; C487216:Pten protein, rat
keywords: PTEN; biomaterials; combination therapy; regeneration; spinal cord injury