远程缺血预处理对大鼠体外循环后肺血管通透性的影响

EFFECTS OF REMOTE ISCHEMIC PRECONDITIONING ON PULMONARY VASCULAR PERMEABILITY OF LUNG INJURY IN RATS UNDERGOING CARDIOPULMONARY BYPASS

目的:探讨远程缺血预处理(RIPC)对大鼠体外循环(CPB)后肺血管通透性的影响。方法:成年雄性SD大鼠60只,随机分为3组:假手术组(S组)、CPB组和RIPC组,每组20只。S组行麻醉和穿刺,但不行CPB;CPB组建立CPB诱发肺损伤模型;RIPC组在实施CPB前对后肢进行RIPC(使用驱血带阻断后肢血流15min,复灌15min,双侧后肢交替进行,每侧3次)。麻醉复苏后2h,处死大鼠并收集支气管肺泡灌洗液(BALF),测定其中白细胞计数、总蛋白浓度、TNF-α和IL-6浓度;取肺组织,测定肺组织伊文思蓝(EB)含量和肺湿/干质量比(W/D比值);光镜下观察肺组织病理学改变。结果:与S组比较,CPB组和RIPC组BALF白细胞计数、总蛋白浓度、TNF-α和IL-6浓度显著升高(P<0.05),肺组织EB含量和W/D比值显著升高(P<0.05);与CPB组比较,RIPC组BALF白细胞计数、总蛋白浓度、TNF-α和IL-6浓度显著下降(P<0.05),肺组织EB含量和W/D比值显著下降(P<0.05)。HE染色显示RIPC组肺组织的形态学损伤较CPB组减轻。结论:RIPC可明显降低大鼠CPB后肺血管通透性,其机制与抑制CPB后肺组织炎性反应有关。

Objective： To investigate the effects of remote ischemic preconditioning （RIPC） on pulmonary vascular permeability of lung injury in rats undergoing cardiopulmonary bypass （CPB）. Methods： Sixty male adult Sprague-Dawley rats were randomly divided into 3 groups （ n =20 each） ： Sham operation group （Group S）, Group CPB and Group RIPC. Rats in Group S were anaesthetized and eannulated, but did not undergoing CPB; rats in group CPB were induced lung injury by CPB; rats in group RIPC were subjected to RIPC before CPB. RIPC was used by compressing the two hindlimbs alternately with a tourniquet for three cycles of 15 rain ischaemia followed by 15 rain reperfusion. The bronchoalveolar lavage fluid （BALF） sam- ples were collected to determine the leucocyte count, albumin, TNF-α and IL-6 concentration. The pulmo nary tissue was obtained to observe the Evan＇S blue （EB） and the wet to dry weight ratio （W/D ratio） at 2 h after anesthesia resuscitation. The histopathological changes of lung tissue were also observed. Results： Compared with Group S, the leucocyte count, albumin, TNF-α and IL-6 concentration in BALF, the EB content and W/D ratio in lung tissues were significantly higher in Group CPB and Group RIPC （ P 0.05）. Compared with Group CPB, the leucocyte count, albumin, TNF-α and IL-6 concentration in BALF, the EB content and W/D ratio in lung tissues were significantly lower in Group RIPC （ P 〈0.05）. Compared with Group CPB, the morphological injury of pulmonary tissue was attenuated in Group RIPC. Conclusion.. RIPC can reduce the pulmonary vascular permeability in rats undergoing CPB, the mechanism is closely related to inhibiting the inflammatory response in lung tissues.