血红素加氧酶1在恶性梗阻性黄疸患者小肠黏膜氧化应激损伤中的作用

Heme oxygenase-1 overexpression in patients with malignant obstructive jaundice

目的探讨血红素加氧酶1（HO-1）在恶性梗阻性黄疸（MOJ）患者小肠黏膜表达及其在氧化应激损伤中的作用。方法采用前瞻性研究，收集行内镜下逆行胰胆管造影（ERCP）检查或治疗的恶性胆道梗阻伴黄疸患者15例，恶性胆道梗阻无黄疸患者10例；并以健康体检胃镜检查者10名作为对照组。取十二指肠乳头以下2～5cm肠黏膜组织，应用比色法检测组织丙二醛含量和超氧化物歧化酶（SOD）活性，原位缺口末端标记法（TUNEL）检测细胞凋亡。应用免疫组织化学和蛋白质印迹方法检测小肠黏膜组织HO-1分布及表达变化。结果MOJ伴黄疸患者肠黏膜脂质过氧化产物丙二醛水平（nmol·mg^-1·prot^-1）明显高于无黄疸组和健康对照组（1．79±0．24比1．09±0．28、1．18±0．32，P=0．041）；SOD活力（nmol·mg^-1·prot^-1）则明显低（303±10比398±11、406±11，P=0．017）；肠上皮细胞凋亡率（％）高（69．1-4-5．9比28．6±3．5、10．2±2．5，P〈0．01）。MOJ患者小肠黏膜HO-1阳性表达为细胞核及细胞质呈棕黄色；伴黄疸组小肠黏膜HO-1表达（0．28±0．04）明显高于无黄疸组（0．20±0．04，P〈0．01）和健康对照组（0．13±0．05，P〈0．01）。蛋白质印迹显示伴黄疸组患者小肠黏膜HO-1蛋白表达（％）明显高于其他两组（10．7±0．7比7．6±0．5和3．9±0．4，P〈0．01）。结论MOJ患者小肠上皮细胞存在氧化应激损伤，HO-1蛋白表达随着胆道梗阻的进展明显升高，这可能是减轻肠黏膜损伤的一种保护性反应。

Objective To investigate the role of heme oxygenase-1 （HO-1） in the oxidative stress damage of intestinal mucosa barrier disruption in patients with malignant obstructive jaundice （ MOJ ） . Methods Fifteen jaundiced patients with malignant biliary obstruction undergoing endoscopic retrograde cholangiopancreatography （ERCP） examination or treatment were enrolled. The control group was comprised of 10 healthy subjects with gastroscopy and 10 patients with non-jaundiced biliary obstruction. Patients were subjected to duodenal biopsy to assess the intestinal oxidative stress as estimated by lipid peroxidation （malondialdehyde） and activity of superoxide dismutase （SOD）. Apoptosis of epithelial cell was examined by TdT-mediated dUTP-biotin nick end labeling. Immunohistochemistry and Western blotting were employed to examine the distribution and expression of HO-1 proteins in intestinal mucosa. Results MOJ jaundiced patients presented high levels of intestinal oxidative stress with a significantly increased level of lipid peroxidation[ （ 1.79±0. 24） vs （ 1.09 ± 0. 28） vs （ 1.18± 0. 32） nmol·mg -1 . prot -1, p = 0. 041 ] and a decreased SOD activity [ （ 303 ±10） vs （ 398 ±11 ） vs （406 ± 11 ） nmol ·mg - 1 . prot - 1, p = 0. 0l 7 ]. The apoptotic rate of intestinal epithelial cells was significantly higher in jaundiced group than in non-jaundiced control group. Apoptotic index was （ 69. I± 5.9 ） % , （ 28.6 ± 3.5 ） % and （ 10. 2 ± 2.5 ） % respectively （P 〈 0. 01 ）. The staining of HO-1 was predominantly localized in cytoplasm. In jaundiced patients, HO-1 was obviously elevated than those in the control group （ HO-1 optical density 0. 28 ±0. 04 vs 0. 20 ± 0. 04 vs 0. 13±0. 05） （P 〈 0. 01 ）. Similar outcomes were obtained by quantitative analysis of Western blotting images [HO-1/GAPDH （10.7 ±0.7）% vs （7.6±0.5）% vs （3.9±0.4）%,P〈0.01]. Conclusion MOJ induces intestinal oxidative stress and it may be a key contributing factor to intestinal barrier failure in the patient population. HO-1 protein level is rising with the progression of obstruction. Perhaps HO-1 has a protective effect upon MOJ through anti-oxidative damage.