深低温期间高氧血气管理对停循环兔脑组织的保护作用

Hyperoxia Management During Deep Hypothermia for Cerebral Protection in a Circulatory Arrest Rabbit Model

目的通过研究深低温期间高氧血气管理对深低温停循环(DHCA)兔血气、生化指标、脑组织中超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、脑组织含水量的影响,探讨高氧管理的脑保护作用。方法建立兔DHCA+选择性脑灌注(ASCP)动物模型,将24只11～13周龄雄性新西兰兔(体重2.7～3.4 kg)用随机数字表法分为3组:假手术组(Sham组),ASCP组(S组),ASCP+高氧管理组(SH组),每组8只。术中检测动脉血氧分压(PaO2)、动脉血氧饱和度(SaO2)、颈静脉球血氧分压(PjvO2)、颈静脉球血氧饱和度(SjvO2)和血乳酸(Lac)含量,术后检测脑组织SOD活性、MDA含量和脑组织含水量。结果停循环前、复灌前和复灌5 min SH组PaO2、PjvO2和SjvO2均高于S组和Sham组(P<0.05)。SH组脑组织SOD活性与S组[(213.53±33.52)U/mg.prot vs.(193.02±27.67)U/mg.prot]和Sham组[(213.53±33.52)U/mg.prot vs.(244.38±35.02)U/mg.prot]比较差异无统计学意义(P>0.05),但S组SOD活性低于Sham组(P<0.05)。SH组脑组织MDA含量低于S组[(1.42±0.30)nmol/mg.prot vs.(2.37±0.55)nmol/mg.prot,P<0.05]。结论深低温期间的高氧血气管理在DHCA+ASCP中能提供更好的氧供,有效地提高兔PjvO2和SjvO2,维持脑组织SOD活性,降低MDA含量,具有脑保护作用。

Objective To investigate the cerebral protective effects of hyperoxia management during deep hypothermia circulatory arrest（DHCA）rabbit by the blood gas indexes,superoxide dismutase（SOD）activity and malondialdehyde（MDA）levels of brain,and ratio of water to brain.Methods A DHCA and antegrade selective cerebral perfusion（ASCP）rabbit model was established.Twenty-four 11-13 week-old male New Zealand rabbits（weighing 2.7 to 3.4 kg）were assigned to three groups with a random number table： a sham operation group（Sham group）,an ASCP group（S group）,and an ASCP ＋ hyperoxia management group（SH group）.There were eight rabbits in each group.We recorded the intraoperative values for arterial oxygen pressure（PaO2）,arterial oxygen saturation（SaO2）,jugular venous oxygen pressure（PjvO2）,jugular venous oxygen saturation（SjvO2）and blood lactate level.The brain SOD activity,MDA levels,and ratio of water to brain were measured after the operation.Results Before initiating circulatory arrest,before initiating reperfusion and five minutes of reperfusion,levels of PaO 2,PjvO 2,and SjvO 2 in the SH group were significantly higher than those of the S group and Sham group.SOD activity in the SH group was not significantly different from that of the S group[（213.53±33.52）U/mg.prot vs.（193.02±27.67）U/mg.prot] and Sham group[（213.53±33.52）U/mg.prot vs.（244.38±35.02）U/mg.prot],but the SOD activity in the S group was lower than that in the Sham group（P 0.05）.MDA levels in the SH group were lower than that in the S group[（1.42±0.30）nmol/mg.prot vs.（2.37±0.55）nmol/ mg.prot,P 0.05].Conclusion Our data show that hyperoxia management during DHCA＋ASCP improves rabbits’ PjvO 2 and SjvO 2,maintains brain SOD activity,and decreases brain MDA levels,demonstrating the neuroprotective effects of hyperoxia mangagement.