OBJECTIVE-Increases in brain cyclooxygenase-2 (COX2) are associated with the central inflammatory response and with delayed neuronal death, events that cause secondary insults after traumatic brain injury. A growing literature supports the benefit of COX2-specific inhibitors in treating brain injuries. [5,5-dimethyl-3(3-fluorophenyl)-4(4-methylsulfonyl)phenyl-2( 5 H)-furanone] is a third-generation, highly specific COX2 enzyme inhibitor. DFU treatments (1 or 10 mg/kg intraperitoneally, twice daily for 3 d) were initiated either before or after traumatic brain injury in a lateral cortical contusion rat model.
METHODS-DFU
NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript RESULTS-DFU treatments initiated 10 minutes before injury or up to 6 hours after injury enhanced functional recovery at 3 days compared with vehicle-treated controls. Significant improvements in neurological reflexes and memory were observed. DFU initiated 10 minutes before injury improved histopathology and altered eicosanoid profiles in the brain. DFU 1 mg/kg reduced the rise in prostaglandin E 2 in the brain at 24 hours after injury. DFU 10 mg/kg attenuated injuryinduced COX2 immunoreactivity in the cortex (24 and 72 h) and hippocampus (6 and 72 h). This treatment also decreased the total number of activated caspase-3-immunoreactive cells in the injured cortex and hippocampus, significantly reducing the number of activated caspase-3-immunoreactive neurons at 72 hours after injury. DFU 1 mg/kg amplified potentially anti-inflammatory epoxyeicosatrienoic acid levels by more than fourfold in the injured brain. DFU 10 mg/kg protected the levels of 2-arachidonoyl glycerol, a neuro-protective endocannabinoid, in the injured brain.CONCLUSION-These improvements, particularly when treatment began up to 6 hours after injury, suggest exciting neuroprotective potential for COX2 inhibitors in the treatment of traumatic brain injury and support the consideration of Phase I/II clinical trials.Keywords 2-Arachidonoyl glycerol; Caspase-3; COX2 inhibitor; Eicosanoids; Endocannabinoid; Neuroinflammation; Rat behavior Traumatic brain injury (TBI) initiates a central inflammatory response that results in the increased production of prostaglandins and reactive oxygen species. These products may cause secondary insults to the brain (55,90,94). Cyclooxygenases catalyze the first step in the formation of prostaglandins from arachidonic acid, producing reactive oxygen species in the process. Cyclooxygenase-1 (COX1), present normally in most tissues, is thought to maintain essential physiological functions, such as gastric mucosal integrity, renal function, and platelet homeostasis (87,101). COX2, the inducible isoform, is expressed in the normal brain (30,87) but is rare or absent in most organs under normal conditions. As in the periphery (32,79), COX2 in the brain can be regulated by inflammatory cytokines (87), and prostaglandin production increases in response to pathological conditions of the central nervous system (3,70,72,89,107). ...
