摘要
目的复制低温缺氧后复温供氧诱导的新生大鼠肺出血模型,观察肺组织缺氧诱导因子-1α(hypoxia inducible factor-1α,HIF-1α)及其受控蛋白诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)、内皮素-1(endothelin-1,ET-1)在此病理过程中的动态变化。方法日龄4~6 d Wistar新生鼠80只,随机分为C组(对照组)20只及实验组60只,实验组中再分为H2、H4及H4H2组,各20只。C组置于常温常氧环境6h;H2组单纯低温(10℃)缺氧(5%O2+95%N2)2h;H4组单纯低温缺氧4h;H4R2组低温缺氧4h后复温(37℃)供氧(≥95%O2)2h。实验结束后观察肺组织大体病理及HE染色,免疫组化方法检测肺组织HIF-1α和iNoS蛋白表达,放射免疫法定量测定肺组织ET-1含量。结果C组及H2组无肺出血,H4组45%发生轻度肺出血,H4R2组100%显著肺出血。低温缺氧期HIF-α、iNOS表达水平及ET-1含量呈进行性升高(H2组、H4组与C组R值的95%CI比较,P〈0.05),复温供氧后显著下降(H4R2组与H4组R值的95%CI比较,P〈0.05),但仍高于C组水平(P〈0.05)。HIF-1α与iNOS、ET-1表达均呈正相关(r分别为0.806和0.810,P均〈0.01)。结论低温缺氧后复温供氧能成功复制新生鼠肺出血模型。低温缺氧期HIF-1α可上调iNOS及ET-1水平,ET-1可能诱发氧自由基少量生成而导致程度较轻的肺出血。复温供氧后尽管HIF-1α、iNOS及ET-1均有所下降,但高氧可能已诱发氧自由基的瀑布样反应而最终导致明显肺出血。
Objective To study the dynamic expression of hypoxia inducible tactor-1α,(HIF-1α), reducible nitric oxide synthase (iNOS) and endothelin-1 (ET-1) in the lung tissue of pulmonary hemorrhage newborn rats model induced by rewarming and reoxygenation following hypothermia and hypoxia. Methods Eighty newborn Wistar rats aged 4 to 6 days were randomly divided into control group (group C,n=20) and experiment groups including group H2 (n=20), H4 (n=20) and H4R2 (n=20). Group C was in normal temperature and air environment for 6 hours, while group H2 and H4 were exposed to hypothermia (10℃) and hypoxia (5 % O2 + 95 % N2 ) for 2 or 4 hours and group H4R2 was given rewarmed temperature of 37℃ and hyperoxia (≥95 %O2) for 2 hours after hypothermia and hypoxia for 4 hours. The gross anatomical and histological(HE staining)changes in lungs were observed. The expression of HIF-1α and iNOS protein were detected by immunohistochemical method and the levels of ET-1 were measured by radioimmunoassy method. Results There were no pulmonary hemorrhage in group C and H2, 45 % rats present slight pulmonary hemorrbege in group H4 and all rats occurred serious pulmonary hemorrhage in group H4R2. The expression of HIF-1α,ET-1 and iNOS gradually increased during hypothermia and hypoxia phase (95% CI of R value in group H2 and H4 compared with group C, P〈0. 05). After rewarming and reoxygenation, expression levels of these three proteins decreased dramatically (95% CI of R value in group H4R2 compared with group H4, P〈0.05), but higher than group C (P〈0. 05). There were positive correlation between expression of HIF-1α andiNOS(r=0.806, P〈0.01), ET-1(r=0.810, P〈0.01). Conclusions The HIF-1α could upregulate the expression of iNOS and ET-1 after hypothermia and hypoxia. Although the express of HIF-1αiNOS and ET-1 decrease after rewarming and reoxygenation, cascade action of oxygen free radica triggering by hyperoxia may be had already result in severe pul
出处
《中华围产医学杂志》
CAS
2007年第1期33-36,共4页
Chinese Journal of Perinatal Medicine
基金
广州市重大科技攻关项目资助(编号:穗卫科[1998]6号)