2015 年 34 巻 1 号 p. 14-21
Background：Both dexmedetomidine and hypothermia are known to reduce brain injury following ischemia. We examined whether a combination of dexmedetomidine and hypothermia reduce brain injury after asphyxial cardiac arrest in rats to a greater extent than either treatment.
Methods：Male SD rats were assigned to one of four groups（n = 7 each）；control (C, saline and temporal muscle temperature 37.5℃), dexmedetomidine (D, dexmedetomidine 10μg/kg and 37.5℃), hypothermia (H, saline and 35.0℃), and dexmedetomidine - hypothermia (DH, dexmedetomidine 10μg/kg and 35.0℃). Dexmedetomidine or saline was administered intraperitoneally 30 min before insult. Predetermined temperature was maintained from 30 min before asphyxia until 60 min after resuscitation. Cerebral ischemia was induced with asphyxia of 5 min, resulting in cardiac arrest of about 2 min. Rats were resuscitated by chest compression and intravenous epinephrine. Neurological score was assessed at 24, 48, and 72 hours after insult, and brain was fixed and stained with hematoxylin and eosin.
Results：Neurological scores were greater in groups H and DH than groups C and D at 24 hours after insult (P < 0.05), whereas they were similar at 48 and 72 hours. Percentages of intact neurons in hippocampal CA1 were greater in groups D, H, and DH than group C (P < 0.05).
Conclusions：Dexmedetomidine and hypothermia improved histologic outcome compared with the control group after asphyxial cardiac arrest, whereas the combination of dexmedetomidine and hypothermia provided comparable neuroprotection with either of two therapies alone.
