缺血后处理对大鼠缺血-再灌注肺损伤血红素加氧酶-1表达的影响

Effect of ischemic postconditioning on the expression of heme oxygenase-1 in acute lung ischemia-reperfusion iiyury in rats

目的观察缺血后处理（IPO）对大鼠肺缺血-再灌注损伤（IRI）期间血红素加氧酶-1（HO-1）表达的影响，探讨其保护机制。方法48只成年SD大鼠，随机（随机数字法）分成6组（n=8）,假手术组（S组）；缺血-再灌注组（I/R组）：夹闭左肺门缺血45min,再灌注105min；缺血后处理组（IPQ组）：缺血后再灌注30s,停灌30s，反复3次，再恢复灌注102min;氯化高铁血红素（Hemin）＋缺血-再灌注组（ZnPPIX＋IPO组）：术前连续2d腹腔注射Hemin40junol/（kg·d）,余同I/R组；锌原卟啉K＋缺血后处理组（ZnPPK＋IPO组）：术前24h腹腔注射ZnPPIX20mg/（kg·d）,余同IPO组；氯化高铁血红素＋假手术组（HM＋S组）。测定各组肺组织HO-1蛋白表达水平、动脉血氧分压（Pa02）、肺组织湿/干质量比（W/D）和血清丙二醛（MDA）含量，观察肺组织病理变化。组间比较采用单因素方差分析，组内比较采用配对＊检验。结果1/R组肺组织HO-1蛋白表达（0.177±0.015）与S组和HM＋S组相比差异具有统计学意义（P〈0.01,P〈0.05）,但与IPO组（0.194士0.017）及HM＋I/R组（0.209±0.013）相比差异具有统计学意义（P〈0.05,P〈0.01）o各实验组Pa02均显著低于S组（90±11）mmHg,IPO组和HM＋I/R组PaO2与1/11组相比较，差异具有统计学意义（P〈0.01）;I/R组较S组肺组织W/D、血清MDA含量升高，肺组织病理损伤严重，而IPO组和HM＋I/R组上述改变差异具有统计学意义（P〈0.05）。结论早期短时程缺血后处理能明显减轻在体大鼠肺IRI,其作用机制与其上调HO-1蛋白表达及抑制脂质过氧化的损伤作用有关。

Objective To investigate the effect of ischemic post-conditioning （IPO） on the level of Heme oxygenase-1 （HO-1） in acute ischemia - reperfusion （ I/R） injury of lung in order to illuminate its protective mechanism. Methods Forty-eight adult SD rats were randomly divided （random number） into 6 groups （n = 8 each） ： sham operation group （ S group） ; I/R group in which the hilum of left lung was clamped for 45 min followed by 105 min reperfusion; IPO group in which left lung hilum was clamped for 45 min and post - conditioned by alternation of 30 s reperfusion with 30 s re-occlusion for three times before perfect perfusion for 102 min; Hemin （ HM） ＋ I/R group; ZnPPIX （ zinc protoporphyrin IX） ＋ IPO group and HM ＋ S group. Arterial partial pressure of oxygen （ Pa02 ） and malondialdehyde （ MDA） content in blood serum were assayed. The left lung was removed for determination of wet/dry （ W/D） lung weight ratio and level of HO-1 protein was detected by immunohistochemical technique and pathohistological changes were observed under light microscopic examination. Comparisons among multiple groups were studied by using one-way analysis of variance （ ANOVA）. Statistical comparisons within groups were analyzed by using paired t - test. Results The level of HO-1 in lung tissue was significantly increased in the I/R group compared with the S group and the HM ＋ S group （P 〈0. 01, F 〈0. 05）. Compared to the 1/ R group,the IPO and the HM ＋ I/R groups had significant higher level of HO-1 （P 〈 0. 05,P 〈 0. 01 ）. The Pa02 was significantly lower in all experimental groups than that in the S group （90 ± 11 ） mmHg. However, the values of Pa02 in the IPO and the HM ＋ I/R groups were higher than that in the I/R group （P 〈0. 01 ） . In addition to severe lung tissue damage evidenced by pathohistological changes, the lung wet/dry （W/D） weight ratio and MDA level in blood serum were significantly higher in the I/R group than those in the S group （P 〈0. 01 ） , whereas the lung damage was attenuated either by IPO or by HM pretreatment （P 〈0. 05,IPO or HM ＋ I/R vs. I/R） . Conclusions IPO can attenuate the lung ischemia - reperfusion injury through upregulating the level of HO-1 protein and inhibiting lipid peroxidation injury.