慢性阻塞性肺疾病患者γ谷氨酰半胱氨酸合成酶活性及表达的变化

目的　研究慢性阻塞性肺疾病(COPD)患者体内氧化/抗氧化状态改变,探讨γ谷氨酰半胱氨酸合成酶(γGCS)及其mRNA在肺内分布及表达变化。方法　(1)收集急性期COPD患者(13例)和普通体检者(9名)血清标本,检测还原型谷胱苷肽(GSH)、活性氧(ROS)、总抗氧化力(TAOC)和γGCS活性;(2)收集肿瘤伴或不伴COPD肺叶切除患者临床标本(COPD组12例,对照组10例),用免疫组化和原位杂交方法检测肺组织中γGCS及γGCSmRNA表达;并进行相关分析。结果(1)急性期COPD患者血清中GSH(2387±386)mg/ml]降低、ROS(2463±199)U/ml]增高、TAOC(534±022)U/ml]降低、γGCS活性(1922±336)U/ml]增强,与对照组分别为(3687±634)mg/ml、(1023±112)U/ml、(1136±107)U/ml和(1237±296)U/ml]比较差异均有统计学意义(P均<005);(2)急性期COPD患者血清中GSH、ROS、TAOC、γGCS活性和一秒钟用力呼气容积占预计值百分比(FEV1占预计值%)、一秒钟用力呼气容积/用力肺活量(FEV1/FVC)、动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)之间无相关性(P>005);(3)原位杂交发现,γGCSmRNA在COPD组肺泡、支气管和炎症细胞中呈高表达吸光度(A)值半定量分析分别为029±005、031±005和028±006],与对照组(分别为014±003、017±004和020±005)比较差异均

Changes of the activity and expression of γ-glutamylcysteine synthetase in patients with chronic obstructive pulmonary disease

OBJECTIVE: To investigate the oxidative/antioxidative status in patients with chronic obstructive pulmonary disease (COPD), and to study the expression and location of gamma-glutamylcysteine synthetase (gamma-GCS) in lung tissues. METHODS: (1) Serum samples of 13 patients with COPD in exacerbation and 9 healthy non-smokers were collected for measurements of the level of reduced glutathione (GSH), reactive oxygen species (ROS), total antioxidative capacity (T-AOC) and gamma-GCS activity. (2) Lung tissues from 22 patients (12 patients with COPD and 10 patients as control) undergoing resection for lung tumor were collected for study of the expression and location of gamma-GCS and gamma-GCS mRNA by immunohistochemistry and in situ hybridization, respectively. RESULTS: (1) Significantly decreased level of GSH (23.87 +/- 3.86) mg/ml], increased level of ROS (2 463 +/- 199) U/ml], decreased T-AOC (5.34 +/- 0.22) U/ml] and enhanced activity of gamma-GCS (19.22 +/- 3.36) U/ml] were shown in the serum of patients with an acute exacerbation of COPD, as compared to the control group (36.87 +/- 6.34) mg/ml, (1 023 +/- 112) U/ml, (11.36 +/- 1.07) U/ml and (12.37 +/- 2.96) U/ml, respectively, all P < 0.05]. (2) There was no relationship between the level of GSH, ROS, T-AOC, gamma-GCS activity in serum and FEV1%, FEV1/FVC, PaO2, PaCO2 of patients with COPD in exacerbation (P > 0.05). (3) In situ hybridization showed that the expressions of gamma-GCS mRNA in alveoli, bronchi and inflammatory cells (A value was 0.29 +/- 0.05, 0.31 +/- 0.05 and 0.28 +/- 0.06, respectively) from the COPD group were stronger than those from the control group (0.14 +/- 0.03, 0.17 +/- 0.04 and 0.20 +/- 0.05, respectively) by semi-quantitative analysis (all P < 0.05). (4) By immunohistochemistry, the expressions of gamma-GCS was significantly higher in alveoli (0.20 +/- 0.04), bronchi (0.18 +/- 0.02) and inflammatory cells (0.25 +/- 0.06) in the COPD group as compared to the control group (0.12 +/- 0.04, 0.10 +/- 0.03 and 0.14 +/- 0.04, respectively, all P < 0.05). (5) Negative correlations were shown between gamma-GCS and FEV1%, FEV1/FVC (r = - 0.501 and - 0.542, respectively, P < 0.05), while the level of gamma-GCS expression had no correlation with FEV1% and FEV1/FVC (r = - 0.221 and - 0.148, respectively, P > 0.05), and a positive relationship was observed between gamma-GCS and gamma-GCS mRNA (r = 0.732, P < 0.05). CONCLUSIONS: Systemic oxidative/antioxidative imbalance occurs in patients with acute exacerbation of COPD, and the total antioxidative capacity decrease may not correlate significantly to the obstruction of airways, in spite of the high level of gamma-GCS activity in serum and gamma-GCS expression in the lungs.