胆碱能抗炎通路对失血性休克/容量复苏大鼠急性肺损伤的影响

Effects of cholinergic antiinflammatory pathway on acute lung injury induced by hemorrhagic shock and resuscitation in rats

摘要:

目的  探讨胆碱能抗炎通路（CAP）对失血性休克/容量复苏（HS/R）诱发的急性肺损伤（ALI）的影响。方法  成年SPF级雄性SD大鼠20只，随机分为迷走神经刺激组（VS组）、迷走神经离断组（VO组）、对照组（SC组）和假手术组（SS组）4组，每组5只。VS组、VO组和SC组通过动脉放血/容量复苏建立失血性休克诱导的ALI模型，容量复苏前VS组电刺激右侧迷走神经15 min，VO组离断右侧迷走神经干，SC组不做特殊处理，SS组不制作ALI模型。分别于放血前（T0）、MAP降至目标值5 min后（T1）、开始复苏前（T2）、复苏至预定血压5 min（T3）、30 min（T4）、90 min（T5）和150 min（T6）等7个时间点测定血浆白介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）水平；于T0、T2和T6抽取动脉血测定氧合指数（OI）；T6处死大鼠后观察肺组织结构病理改变，并测定肺组织核转录因子-κB（NF-κB）含量。结果  T1至T6时段VS组、VO组和SC组IL-6和TNF-α浓度升高，高于SS组（P <0.05）；T3至T6时段SC组IL-6和TNF-α浓度高于VS组（P <0.05），低于VO组（P <0.05）。T6时VS组、VO组和SC组OI均下降，3组均低于SS组（P <0.05）； VO组和SC组OI比较差异无统计学意义（P>0.05），两组均低于VS组（P <0.05）。VS组、VO组和SC组肺组织NF-κB含量增加，高于SS组（P <0.05），VS组、VO组和SC组间NF-κB含量比较差异有统计学意义，SC组高于VS组（P <0.05）、低于VO组（P <0.05）。VS组、VO组和SC组肺损伤评分升高，高于SS组（P <0.05），VS组、VO组和SC组间评分比较差异有统计学意义，SC组高于VS组（P <0.05），低于VO组（P <0.05）。结论  CAP对HS/R大鼠ALI具有一定的保护效应，其机制与NF-κB信号通路调控IL-6和TNF-α等炎症介质的释放有关。

Abstract:

Objective To evaluate the contributions of cholinergic antiinflammatory pathway (CAP) on acute lung injury (ALI) induced by hemorrhagic shock and resuscitation (HS/R) in rats. Methods Twenty SFP adult male Sprague-Dawley rats were randomly divided into four groups (5 in each group): vagal-stimulation group (group VS), vagal-transection group (group VO), control group (group SC) and sham-operation group (group SS). In the groups VS, VO and SC, bloodletting was performed in the rats for hemorrhagic shock and maintained for 60 min, then resuscitation was done with autoblood and normal saline. ALI rat models followed hemorrhagic-shock/resuscitation (HS/R) were established in the groups VS, VO and SC. The rats in the group VS received electric stimuli to right vagus nerve for 15 min before the onset of resuscitation, the rats in the group VO received vagotomy of right vagus trunk instead before the onset of resuscitation, and the rats in the group SC received no additional treatments. The rats in the group SS experienced no HS/R for ALI. Blood samples were collected via the carotid artery to monitor plasma concentrations of IL-6 and TNF-α before bleeding (T0), 5 minutes after MAP reached target value (T1), before resuscitation of shock (T2), 5 min (T3), 30 min (T4), 1.5 h (T5) and 2.5 h (T6) after resuscitation. Arterial blood gas analyses were detected and oxygenation index (OI) was calculated at T0, T2 and T6. The lungs were harvested for both measurement of NF-κB level and observation of pathological changes of lungs at T6. Results The plasma IL-6 and TNF-α levels were significant increased in the groups VS, VO and SC from T1 to T6 (P < 0.05) and were higher than the corresponding ones in the group SS (P < 0.05). IL-6 and TNF-α levels in the group SC were notably higher than those in the group VS but lower than those in the group VO from T3 to T6 (P < 0.05). At T6, the OI in the groups VS, VO and SC were decreased and obviously lower than that in the group SS (P < 0.05), and there was no significant difference in OI between the groups VO and SC (P > 0.05); but the values of OI in the groups VO and SC were significantly lower than that in the group VS (P < 0.05). The content of lung NF-κB raised in the groups VS and VO and SC and exceeded that in the group SS (P < 0.05). There were obvious differences in the content of lung NF-κB among the groups VS, VO and SC (P < 0.05); the content of lung NF-κB in the group SC was significantly higher than that in the group VS (P < 0.05), but significantly lower than that in the group VO (P < 0.05). The histologic scores of lung injury in the groups VS, VO and SC were higher than those in the group SS (P < 0.05), and the scores in the group SC were higher than those in the group VS (P < 0.05) but lower than those in the group VO (P < 0.05). Conclusions The CAP has potential protective effects against ALI induced by HS/R, and its mechanisms are relevant to the regulation of the production of IL-6 and TNF-α by NF-κB signal way in lungs.