The neuroprotective effect of xenon administration during transient middle cerebral artery occlusion in mice

Background: Xenon has been shown to be neuroprotective In several models of in vitro and in vivo neuronal injury. However, its putative neuroprotective properties have not been evaluated in focal cerebral ischemia. The purpose of this study was to determine if xenon offers neuroprotection in a mouse model of middle cerebral artery occlusion. Methods. C57BL/6 mice underwent 60 min of middle cerebral artery occlusion. The animals (n = 21 per group) were randomized to receive either 70% xenon + 30% O-2, 70% N2O + 30% O-2, or 35% xenon + 35% N2O + 30% O-2. After 24 h, functional neurologic outcome (on three independent scales: four-point, general, and focal deficit scales) and cerebral infarct size were evaluated. Results: The 70% xenon + 30% O-2 group showed improved functional outcome (median [interquartile range], four-point scale. 2 [2], 70% xenon + 30% O-2 versus 3 [2], 70% N2O + 30% O-2, P = 0.0061; general deficit scale: 9 [6], 70% xenon + 30% O-2 versus 10 [4], 70% N2O + 30% O-2, P = 0.0346). Total cerebral infarct volumes were reduced in the 70% xenon + 30% O-2 group compared with the 70% N2O + 30% O-2 group (45 +/- 17 mm(3) versus 59 +/- 11 mm(3), respectively; P = 0.0009). Conclusions. in this model of transient focal cerebral ischemia, xenon administration improved both functional and histologic outcome.