局部低温对失血性休克兔肢体缺血再灌注损伤的影响

Effect of regional hypothermia on limb ischemia-reperfusion injury in a rabbit model of hemorrhagic shock

摘要：目的 评价局部低温对失血性休克兔肢体缺血再灌注损伤的影响.方法 健康成年新西兰大白兔18只,体重2.0- 2.5 kg,雌雄不拘,采用随机数字表法分为3组（n=6）：假手术组（S组）、肢体缺血再灌注组（I/R组）和局部低温组（RH组）.I/R组和RH组使用7.62 mm滑膛枪0.25 g钢珠弹射击左后肢大腿中下1/3肌肉丰富处.致伤后待血压稳定30 min时,经右股动脉以2 ml/min的速率抽血,直至MAP降至45 - 50 mmHg.稳定10 min时,使用橡皮管止血带结扎左后肢根部.RH组在使用止血带后对伤肢进行降温4h,维持皮下温度9-11℃.止血带使用4h后恢复灌注6h.分别于股动脉/静脉置管术后即刻（T0）、再灌注2、4和6 h（T1-3）时,经右股动脉取血样,行血气分析,采用ELISA法检测血清TNF-α、IL-2和IL-6的浓度.于T3时处死动物,取右肺下叶边缘组织,光镜下观察病理结果,并行肺损伤评分,测定肺组织湿重/干重（W/D）比值.结果 与S组比较,I/R和RH组T2,3时呼吸频率升高,PaCO2降低,肺损伤评分和肺组织W/D比值升高,T1-3时血清TNF-α、IL-2和IL-6浓度升高（P＜0.05）;与I/R组比较,RH组T22时呼吸频率降低,PaCO2升高,肺损伤评分和肺组织W/D比值降低,T1-3时血清TNF-α、IL-2和IL-6浓度降低（P＜0.05）,肺组织病理学损伤减轻.结论 局部低温可减轻失血性休克兔肢体缺血再灌注损伤,其机制可能与抑制全身炎症反应有关.

Objective To evaluate the effect of regional hypothermia on limb ischemia-reperfusion （I/R） injury in a rabbit model of hemorrhagic shock.Methods Eighteen healthy adult New Zealand white rabbits of both sexes,weighing 2.0-2.5 kg,were divided into 3 groups （n=6 each） using a random number table：sham operation group （S group）,limb I/R group （I/R group） and regional hypothermia group （RH group）.Rabbits were shot with 0.25 g steel ball with a 7.62 mm smoothbore at the middle and lower 1/3 of the left hindlimb in I/R and RH groups.When the blood pressure was stable for 30 min after injury,blood was drawn via the right femoral artery at a rate of 2 ml/min until mean arterial pressure decreased to 45-50 mmHg.Then a rubber tourniquet was used to ligate left hindlimbs 10 min later.The injured limb was cooled down for 4 h after applying tourniquet to maintain the subcutaneous temperature at 9-11 ℃ in group RH.After tourniquet was applied for 4 h,perfusion was restored and lasted 6 h.After catheterization （T0） and at 2,4 and 6 h of reperfusion （T1-3）,blood samples were collected from the right femoral artery for blood gas analysis and for determination of tumor necrosis factor-α （TNF-α）,interleukin-2 （IL-2） and IL-6 concentrations in serum （by enzyme-linked immunosorbent assay）.The animals were sacrificed at T3,and tissues around the margin of the inferior lobe of right lung were obtained for examination of the pathological changes which were scored and for determination of wet to dry weight ratio （W/D ratio）.Results Compared with group S,the respiratory rate was significantly increased and PaCO2 was decreased at T2,3,the pathological score and W/D ratio were increased,and the concentrations of TNF-α,IL-2 and IL-6 in serum were increased at T1-3 in I/R and RH groups （P〈0.05）.Compared with group I/R,the respiratory rate was significantly decreased and PaCO2 was increased at T2,3,the pathological score and W/D ratio were decreased,and the concentrations of TNF-α,IL-2 and IL-6 in serum were decreased at T1-3 （P〈0.05）,and the pathological score was significantly attenuated in group RH.Conclusion Regional hypothermia can reduce limb I/R injury in a rabbit model of hemorrhagic shock,and the mechanism may be related to inhibiting systemic inflammatory responses.