限制性输液对失血性休克急性肺损伤的保护作用

The protective effect of limited fluid resuscitation on hemorrhagic shock induced lung injury in mice

目的：探讨限制性输液对失血性休克小鼠急性肺损伤（ acute lung injury ， ALI）的保护作用。方法健康C57 BL/6小鼠32只随机分为以下四组：对照组（ A组）、休克组（ B组）、限制性输液组（ C组）和大量输液组（ D组）。分别于失血性休克120 min后接受不同的液体复苏方案，6h后处死动物，观察肺病理学改变，测定支气管肺泡灌洗液中总蛋白水平、白细胞计数、肺湿干重比值（ W/D）和中性粒细胞髓过氧化物酶（ MPO）活性。分别应用Western blot和RT-PCR检测肺组织高迁移率族蛋白B1（highobility group box1， HMGB1）和mRNA的表达，用Western blot检测肺组织p38的激活情况。在此基础上应用p38抑制剂SB203580观察对HMGB1表达的影响。结果 A组小鼠镜下可见正常肺组织，B组肺组织呈明显的炎性改变，与B组比较，C组肺病理学改变明显减轻，而D组未见明显改变。与A组比较，B组总蛋白水平、白细胞计数、肺W/D、MPO活性、HMGB1和mRNA表达以及p38激酶活性均明显增加（P＜0．05）；与B组比较，C组上述各指标均明显降低（P＜0．05），而D组上述指标的变化差异无统计学意义（P＞0．05）。与对照组比较，SB203580组HMGB1表达显著降低（ P＜0．05）。结论限制性输液可改善失血性休克小鼠肺内炎症反应，可能与通过p38信号通路，抑制HMGB1表达有关。

Objective To investigate the protective effect of limited fluid resuscitation on hemorrhagic shock induced lung injury in mice .Methods Thirty-two healthy C57BL/6 mice were randomly divided into 4 groups （n =8 each）： group A, control;group B, hemorrhagic shock; group C, hemorrhagic shock with limited fluid resuscitation and group D , hemorrhagic shock with traditional fluid resuscitation .The animals were resuscitation for 6 h and then all animals were sacrificed .Lung wet and dry weight ratio （ W/D ） was calculated , and lung pathologic changes were observed under light microscope .Total protein and WBC in bronchoalveolar lavage fluid （ BALF ） were determined .The expression of high mobility group box 1 （ HMGB1 ） and p -p38 protein and mRNA was measured by Western blot and RT-PCR, respectively.A p38 inhibitor SB203580 was used to investigate the effect on HMGB1 expression .Results Normal lung tissues were observed in group A .Significant pathological changes were observed in group B and D and milder changes were revealed in group C .Compared with group A, total protein and WBC in BALF , W/D lung weight ratio and MPO activity were significantly higher in group B （ P 〈0.05 ）; HMGB1 protein and mRNA expression and p -p38 activity also significantly increased in group B （P〈0.05）.Compared with group B, the above indexes significantly decreased in group C （P〈0.05）, however, no significant changes were observed in group D （P〉0.05 ） .Compared with control group , the expression of HMGB1 protein significantly decreased in＆amp;nbsp;SB203580 treatment group . Conclusion Limited fluid resuscitation attenuated hemorrhagic shock induced acute lung injury, and the underlying mechanism might be down -regulation of HMGB1 through p38 MAPK signal pathway .