Trans-activator of transcription-mediated delivery of NEP1-40 protein into brain has a neuroprotective effect against focal cerebral ischemic injury via inhibition of neuronal apoptosis

Abstract

Background: The Nogo-66 antagonistic peptide (NEP1-40) is a potential candidate for therapeutic intervention of neuronal injury. However, delivery of the proteins across the blood-brain barrier is severely limited by its size and biochemical properties. The current study was designed to evaluate the transducible effects of the trans-activator of transcription (TAT) transduction system for NEP1-40 to cross the blood-brain barrier and to clarify whether Intraperitoneal administration of TAT-NEP1-40 could protect cerebral neurons from Ischemic Injury. Methods: Adult male Sprague-Dawley rats were submitted to a 120-min focal ischemia and received an intraperitoneal Injection of No-TAT-NEPl-40, TAT-NEP1-40, TAT-β-galactosidase, or vehicle. The existence of the proteins In the brain was analyzed with immunofluorescence and Western blot techniques at 6 h after injection. Brain Ischemic Injury was evaluated by neurologic deficit scores, Infarction volumes, terminal deoxynucleotldyl transferase-mediated dUDP-biotin nick end labeling staining, and assay of caspase-3 activity. Results: Western blot analysis and immunofluorescence staining confirmed the presence of TAT-NEP1-40 protein in the brains 6 h after injection. Intraperitoneal injection of TATNEP1-40 could attenuate the numbers of terminal deoxynucleotldyl transferase-mediated dUDP-biotin nick end labellng-positive cells and activated caspase-3 positive cells, and increase the viability of the cells in the ischemic bounder zone, compared with that treated with No-TAT-NEPl-40, TAT-β-Gal, or vehicle. Furthermore, treatment with TAT-NEP1-40 significantly Im-proved the neurologic outcomes and reduced the size of the infarction in rats. Conclusions: The results demonstrate that the TAT-NEP1-40 could be efficiently delivered into the rat brains and improve ischemia-induced neurologic outcomes through attenuating cell apoptosls in Ischemic brains. Copyright © 2008, the American Society of Anesthesiologists, Inc.