Reduced cortical injury and edema in tissue plasminogen activator knockout mice after brain trauma

Tissue plasminogen activator (tPA) may play a deleterious role after brain injury. Here, we compared the response to traumatic brain injury in tPA knockout (KO) and wildtype (WT) mice after controlled cortical impact. At 6 h after trauma, blood-brain barrier permeability was equally increased in all mice. However, by 24 h specific gravity measurements of brain edema were significantly worse in WT mice than in KO mice. At 1 and 2 days post-trauma, mice showed deficits in rotarod performance, but by day 7 all mice recovered motor function and there were no differences between WT and KO mice. At 7 days, cortical lesion volumes were significantly reduced in KO mice compared with WT mice. However, there were no significant differences: in CA3 hippocampal neuron survival. These data suggest that tPA amplifies cortical brain damage and edema in this mouse model of traumatic brain injury. NeuroReport 12:4117-4120 (C) 2001 Lippincott Williams & Wilkins.