动脉血二氧化碳分压对大鼠脑组织细胞CYP4A分布的影响  

Effect of different carbon dioxide partial pressure in arterial blood on CYP4A in rat brain tissue

作　　者：孟丽巍[1] 齐丽[2] 李逸飞[1] 朱大岭[3] 

机构地区：[1]哈尔滨医科大学附属第一医院麻醉科,黑龙江哈尔滨150001 [2]齐齐哈尔医学院综合临床护理学教研室,黑龙江齐齐哈尔161006 [3]哈尔滨医科大学大庆分院,黑龙江大庆163000

出　　处：《哈尔滨医科大学学报》2011年第2期124-127,共4页Journal of Harbin Medical University

基　　金：黑龙江省自然科学基金项目(D0316);黑龙江省政府博士后启动金研究项目(LRB2004121)

摘　　要：目的观察不同动脉血二氧化碳分压（PaCO2）对细胞色素P4504A（CYP4A）在大鼠脑组织细胞中表达的影响,为进一步证明20-羟廿碳四烯酸（20-HETE）在CO2引起脑血管反应机制中作为介导因子发挥重要作用提供理论依据。方法健康成年雄性Wistar大鼠30只,体重200-250 g,随机分为A,B,C3组（n=10）：A组为正常二氧化碳组（对照组）、B组为低碳酸血症组,C组为高碳酸血症组。A组吸入气体为50%O2和50%N2,潮气量6-10 mL/kg,维持动脉血二氧化碳分压（PaCO2）在40-45 mmHg;B组吸入气体为50%O2和50%N2,过度通气使PaCO2下降至20~25 mmHg;C组吸入气体为5% CO2,50% O2和45% N23种混合气,调整呼吸参数使PaCO2上升至60~65 mmHg。3%戊巴比妥腹腔注射麻醉大鼠,气管插管后机械通气,吸∶呼比设定为1∶1,呼吸频率45-55次/分,操作稳定30 min后开始记录各生理指标。3 h后放血处死大鼠,采用免疫组织化学法测定大鼠脑组织中CYP4A蛋白的表达。结果 3组血流动力学和体温无明显差异（P〉0.05）。与A组比较,B组动脉血pH值升高、PaCO2降低,脑组织CYP4A蛋白表达增多（P〈0.05）;C组pH值降低、PaCO2升高,CYP4A蛋白表达减少（P〈0.05）。结论高碳酸血症时,CO2抑制CYP4A在脑内的表达;低碳酸血症时,CO2促进CYP4A在脑内的表达。Objective To confirm the relation between 20-hydroxyeicosatetraenoic acid（20-HETE） and different carbon dioxide partial pressure in arterial blood through studying the expression of CYP4504A（CPY4A） in different carbon dioxide partial pressure in arterial blood in rat brain for further investigating the mechanism of hypocapnia-induced cerebral vessels construction.Methods Thirty adult male Wistar rats weighing 200 to 250 g were randomized into 3 groups： group A（control group）,PaCO2 was maintained at approximately 40~45 mmHg and mechanical ventilated with 6~10 mL/kg tidal volume and the breath rate 45~55 per mintue;group B（hypocapnia group）,PaCO2 was at approximately 20~25 mmHg by adjusting breath rate with inspiring the mix-ture of 50% O2 and 50% N2;group C（hypercapnia group）,PaCO2 was at approximately 60~65 mmHg with inspiring the mixture of 50% O2,45% N2,5%CO2;In group C 5% CO2 was introduced into the inspiratory limb of the ventilator circuit to maintain hypercapnia.The animals were anaesthetized with intraperitoneal 3% napental,tracheostomized and mechanical ventilated for 3 h（I∶E=1∶1,FiO2=0.50,nitrogen balanced）.After reaching each PaCO2 level for 30 min physiology data were recorded.The head was removed for determination of CYP4A in brain tissue by immunohistochemistry.Results There were no significant differences among 3 groups about MAP and temperature（P0.05）.Compared with group A,group B had higher pH,lower PaCO2 and group C had lower pH,higher PaCO2（P0.05）;The expression of CYP4A protein in brain tissue significantly increased in group B and decreased in group C as compared with group A（P0.05）.Conclusion CO2 can decrease the expression of CYP4A in brain tissue in hypercapnia and increase the expression of CYP4A in hypocapnia.

关 键 词：动脉血二氧化碳分压 细胞色素P4504A 20-羟廿碳四烯酸 脑组织 

分 类 号：R-332[医药卫生] R614.1