Abstract
Abstract: :
Purpose: Optic tract regeneration. A tissue gap caused by deep transections of the optic tract (OT) in the midbrain can completely block the re-innervation of the superior colliculus (SC) by the retina, even when done at young ages when the axons have regenerative potential. We find that a self-assembling peptide (SAP) nanofiber scaffold can facilitate the reconstruction of a tissue substrate that supports regeneration across the tissue disruption. Methods: Brain wounds were inflicted in postnatal day-2 Syrian hamsters anesthetized by whole-body cooling. The scalp was opened and the OT within the SC was completely severed with a deep knife wound through a surgical opening in the cartilaginous skull, extending 1-2 mm below the surface from the midline to a point beyond the lateral margin of SC. Animals survived 1, 3, 6, 30 and 60 days. At surgery, 10 animals were treated by injection into the brain wound of 10 ul of 1% SAP RAD16-I. Control animals with the same lesion included 3 with isotonic saline injection (10 ul), and 27 earlier cases with knife cuts and no injection, surviving 6-9 days. Results: Histological results revealed that only in the animals treated with SAP alone, the tissue appears to have reconnected across the lesion at all survival times (Χ2=34.8, df (1), p<<0.001). The tissue bridges supported partial re-innervation of the caudal SC by the severed retinofugal axons. Conclusion: Thus, the SAP is shown to offer a new means of ameliorating the tissue disruptions caused by traumatic injury to the CNS, allowing regrowth of axons that have regenerative potential.
Keywords: wound healing • trauma • animal model