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

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2～5 cm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±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.

Heme oxygenase-1 overexpression in patients with malignant obstructive jaundice

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. Immunohislochemistry 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=0.017]. The apoptotic rate of intestinal epithelial cells was significantly higher in jaundiced group than in non-jaundiced control group. Apoptotic index was (69. 1 ± 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 anli-oxidative damage.