Identifying the Long-Term Role of Inducible Nitric Oxide Synthase after Contusive Spinal Cord Injury Using a Transgenic Mouse Model

This study investigates the long-term effects of iNOS ablation after spinal cord injury (SCI) using inos-null mice. Locomotor function was assessed weekly, and at the endpoint (six weeks), the volume of preserved white and gray matter, as well as the number of dorsal column axons and perilesional blood vessels rostral to the injury, were quantified. At weeks two and three after SCI, iNOS−/−mice exhibited a significant locomotor improvement compared to WT controls, although a sustained improvement was not observed during later weeks. At the endpoint, iNOS−/−mice showed significantly less preserved white and gray matter, as well as fewer dorsal column axons and perilesional blood vessels, compared to WT controls. While short-term antagonism of iNOS provides histological and functional benefits, its long-term ablation after SCI may be deleterious, blocking protective or reparative processes important for angiogenesis and tissue preservation.

• 1
  iNOS−/− mice exhibited less preserved white and gray matter at six weeks post-SCI compared to wild-type controls.
• 2
  iNOS−/− mice had fewer dorsal column axons and perilesional blood vessels rostral to the lesion than wild-type controls.
• 3
  iNOS−/− mice showed an acute improvement in functional recovery after SCI within the first few weeks, but this improvement did not persist long-term.