Bradykinin antagonist decreases early disruption of the blood-spinal cord barrier after spinal cord injury in mice.

Bradykinin is one of the key molecules involved in the disruption of the blood-brain barrier and blood-spinal cord barrier occurring after spinal cord injury (SCI). Previously we have shown a biphasic opening of the blood-spinal cord barrier as well as increased transport of tumor necrosis factor-alpha (TNFalpha) after SCI by compression of the lumbar spinal cord in mice. To evaluate the role of bradykinin in the two phases of blood-spinal cord barrier disruption, we pretreated mice with a potent bradykinin antagonist, the decapeptide B9430, before SCI. Our results show that B9430 decreased the general blood-spinal cord barrier disruption occurring immediately after SCI but failed to affect the delayed opening of the blood-spinal cord barrier observed 72 h after SCI. By contrast, the entry of TNFalpha after SCI was not affected by B9430 treatment. We conclude that bradykinin is involved in the early phase of blood-spinal cord barrier disruption, with B9430 non-selectively blocking this early disruption without affecting the selective transport system for TNFalpha. This indicates the therapeutic potential of bradykinin antagonists in ameliorating tissue damage induced by SCI.