改良超滤对体外循环诱发犬肺损伤时水通道蛋白1表达的影响

Effects of modified ultrafiltration on expression of aquaporin 1 in cardiopulmonary bypass-induced lung injury in dogs

目的 评价改良超滤对体外循环（CPB）诱发犬肺损伤时水通道蛋白1（AQP1）表达的影响.方法 健康成年杂种犬18只,体重15 ～ 20 kg,雌雄不拘,采用随机数字表法,将其分为3组（n=6）：对照组（C组）、体外循环组（CPB组）和改良超滤组（MUF组）.C组只开胸,余两组开胸并建立犬CPB模型,MUF组于CPB停机后10～ 15 min内进行改良超滤,于开胸后行机械通气前（T1）、CPB停机（T2）和停机后1 h（T3）时抽取股动脉血行血气分析,计算呼吸指数（RI）和氧合指数（OI）,光镜下观察肺组织病理学结果,采用RT-PCR法检测肺组织AQP1 mRNA表达.结果 与T1时比较,CPB组和MUF组T2,3时RI和OI升高,肺AQP1 mRNA表达下调（P＜0.05）；与C组比较,CPB组和MUF组T2,3时RI升高,肺AQP1 mRNA表达下调,CPB组T2,3时、MUF组T2时OI降低（P＜0.05）；与CPB组比较,MUF组T3时RI降低,OI升高,AQP1 mRNA表达上调（P＜0.05）.结论 改良超滤可减轻CPB诱发犬肺损伤,机制可能与上调肺组织AQP1表达有关.

Objective To evaluate the effects of modified ultrafiltration on the expression of aquaporin 1 （AQP1） in cardiopulmonary bypass （CPB）-induced lung injury in dogs.Methods Eighteen healthy adult dogs of either sex,weighing 15-20 kg,were randomly divided into 3 groups （n =6 each）：control group （group C）,group CPB and modified ultrafiltration group （group MUF）.The dogs were anesthetized with intraperitoneal 2.5%pentobarbital 25 mg/kg.Thoracotomy was performed in all the three groups and in addition lung injury was produced by CPB in CPB and MUF groups.In group MUF,modified ultrafiltration was performed at 10-15 min after termination of CPB.Arterial blood samples were collected before mechanical ventilation （T1）,at end of CPB （T2）,and at 1 h after termination of CPB （T3） to calculate respiration index （RI） and oxygenation index （OI）.The lungs were removed for microscopic examination of pathologic changes in lung tissues under light microscope and for detection of AQP1 mRNA expression by real-time PCR.Results RI and OI were significantly higher and AQP1 mRNA expression was lower at T2 and T3 than at T1 in CPB and MUF groups （P 〈 0.05）.Compared with group C,RI was significantly increased and AQP1 mRNA expression was down-regulated at T2,3 in CPB and MUF groups,and OI at T2.3 in CPB group and at T2 in MUF group was decreased （P 〈 0.05）.Compared with group CBP,RI was significantly decreased,OI was increased and AQP1 mRNA expression was up-regulated at T3 in group MUF （P 〈 0.05）.Conclusion Modified ultrafiltration can reduce CPB-induced lung injury in dogs and upregulation of AQP1 may be involved in the mechanism. Keywords：Ultrafiltration ; Cardiopulmonary bypass ; Aquaporin 1