Perfluorocarbon Emulsion Improves Cerebral Oxygenation and Mitochondrial Function after Fluid Percussion Brain Injury in Rats

OBjECTIVE: Cerebral ischemia is a common secondary sequela of traumatic brain injury (TBI). Experimental models of stroke have demonstrated reductions in ischemia after perfluorocarbon (PFC) administration; however, there are no published reports of PFC efficacy after TBI. The current study analyzed the effect of the PFC emulsion Oxygent (AF0144; Alliance Pharmaceutical Corp., San Diego, CA) on cerebral oxygenation, mitochondrial redox potential, and free radical formation after lateral fluid percussion injury. METHODS: After fluid percussion injury, five 2.25 ml/kg doses of PFC or saline were administered to rats breathing 100% O₂, and oxygen tension was recorded. In a second experiment, a single bolus (11.25 ml/kg) of PFC or saline was given after injury, and redox potential and free radical formation were measured at 1 or 4 hours with Alamar blue dye and dihydrorhodamine 123, respectively. RESULTS: Cerebral oxygen tension was significantly increased in both injured and sham animals treated with 11.25 ml/kg of PFC as compared with saline (P < 0.05). Likewise, PFC significantly increased mitochondrial redox potential as compared with saline at 4 hours after injury (P < 0.01). Mitochondrial peroxynitrite and peroxide production also increased with the administration of PFC (P < 0.05). CONCLUSION: The current study demonstrates that a PFC emulsion can significantly increase cerebral oxygenation after TBI and enhance mitochondrial function at 4 hours after injury as compared with saline. This study demonstrates a new therapeutic potential for PFC to enhance cerebral oxygenation and aerobic metabolism after TBI. However, the increased free radical formation with high-dose PFCs suggests the need for further studies combining PFCs with free radical scavengers.