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Endothelin-1和Prostacyclin在慢性阻塞性肺疾病发病机制中的作用研究

Endothelin-1 and Prostacyclin are Involved in the Pathogenesis of Chronic Obstructive Pulmunary Disease

【作者】 陈燕

【导师】 陈平;

【作者基本信息】 中南大学 , 呼吸内科, 2009, 博士

【摘要】 第一章慢性阻塞性肺疾病患者内皮素-1的表达及意义目的观察吸烟者和慢性阻塞性肺疾病(COPD)患者支气管肺泡灌洗液(BALF)、诱导痰和血浆中内皮素-1(endothelin-1,ET-1)的浓度变化,探讨ET-1在COPD发病机制中的临床意义。方法本研究选择健康吸烟者14例,COPD患者13例,同时选择14例健康人为正常对照组,用支气管肺泡灌洗术(BAL)收集BALF对其细胞成分进行计数和分类,用高渗盐水诱痰法取痰标本并进行细胞计数和分类,用放射免疫法测定BALF、诱导痰和血浆中ET-1浓度。结果1.COPD组一秒钟用力呼气量占预计值%(FEV1%pre)、一秒率(FEV1/FVC%)及呼气峰值流速占预计值%(PEF%pre)较正常对照组和吸烟组明显降低(p均<0.01),而正常对照组与吸烟组之间差异无显著性(p>0.05)。2.吸烟组、COPD组BALF和诱导痰中细胞总数、肺泡巨噬细胞(AM)数及中性粒细胞(PMN)数均明显高于正常对照组(p均<0.05)。3.正常对照组、吸烟组和COPD组BALF中ET-1浓度无显著性差异,吸烟组及COPD组诱导痰中ET-1浓度较正常对照组明显增高,差异有统计学意义(p均<0.05),COPD组血浆中ET-1浓度较正常对照组和吸烟组明显增高(p<0.05)。4.诱导痰中AM数与肺功能气流阻塞指标FEV1%pre、FEV1/FVC%呈负相关(r=-0.480,r=-0.545,p均<0.01)。PMN数与FEV1%pre、FEV1/FVC%呈负相关(r=-0.677,r=-0.773,p均<0.01)。诱导痰和血浆中ET-1浓度与FEV1%pre值呈负相关(r=-0.723,r=-0.801,p均<0.01),诱导痰中ET-1浓度与AM数和血浆中的ET-1浓度呈正相关(r=0.543,r=0.864,p均<0.01)。结论1.吸烟者和COPD存在以AM和PMN浸润为主的慢性气道炎症,AM、PMN可能参与了COPD气流阻塞的形成。2.ET-1可能通过参与气道炎症和气流阻塞在COPD发生发展中起着重要作用。第二章慢性阻塞性肺疾病患者肺组织中前列环素的表达及意义目的观察COPD患者肺组织前列环素合酶(prostacyclin synthase,PGI2S)表达及组织上清液中前列环素(prostacyclin,PGI2)稳定的代谢产物6-酮前列腺素F1α(6-keto-PGF1α)浓度变化,探讨COPD患者PGI2的表达及意义。方法本研究选择中南大学湘雅二医院胸外科2008年6月至2008年10月因肺癌和肺大疱行肺叶切除术的患者22例,根据COPD的诊断标准,分为COPD组和对照组。免疫组织化学染色检测PGI2S的表达,酶联免疫吸附试验(ELISA)测定肺组织上清液中6-keto-PGF1α含量。结果1.对照组和COPD组吸烟指数分别为(341.2±80.8)年支和(570.2±172.6)年支,COPD组与对照组有显著性差异(p<0.05)。COPD组FEV1%pre和FEV1/FVC%与对照组有显著性差异(p均<0.05)。2.COPD组肺组织中型血管、微小型血管内皮细胞和气道上皮细胞PGI2S表达较对照组明显降低(p均<0.05)。3.COPD组肺组织上清液中6-keto-PGF1α较对照组下降,差异有统计学意义(p<0.05)。结论COPD肺组织PGI2表达下调,PGI2在COPD发病机制中可能起着重要作用。第三章ET受体拮抗剂在香烟提取物所致肺气肿模型中的保护作用及其机制研究目的探讨ETA受体拮抗剂BQ123和非选择性(ETA/B)受体拮抗剂Bostentan(Bos)对香烟提取物(CSE)所致肺气肿模型肺气肿程度、肺泡间隔细胞凋亡、caspase-3表达、基质金属蛋白酶-2,9(MMP-2,9)活性、炎症因子肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)表达及血清抗氧化能力的影响。方法将24只Sprague-Dawley大鼠按随机数字表法分为对照组、CSE组及BQ123干预组和Bos干预组,每组各6只。CSE组、BQ123和Bos干预组连续三周每周一次腹腔内注射CSE,此外BQ123干预组连续三周每天腹腔内注射BQ123 1mg/kg/day,Bos干预组每天胃管内给药Bos 100mg/kg/day。病理切片苏木素-伊红(HE)染色后测定平均内衬间隔(MLI)和肺泡破坏指数(DI)评估肺气肿程度。采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测凋亡并计算凋亡指数(apoptotic index,AI);用免疫组织化学测定促凋亡基因caspase-3在肺组织的表达,Western blotting测定肺组织匀浆中caspase-3的蛋白表达;采用明胶酶谱法测定肺组织匀浆中MMP-2和MMP-9活性;采用ELISA测定肺组织匀浆中TNF-α和IL-1β的浓度;采用Bioantioxidant Power(BAP)试验检测血清抗氧化能力。结果1.3周后CSE组大鼠肺组织呈现肺气肿病理改变,BQ123和Bos干预组病理变化相对减轻。CSE组MLI和DI较对照组显著增高(p均<0.01)。BQ123和Bos干预组MLI和DI较CSE组显著降低(p均<0.01),但BQ123组和Bos组两组间无统计学差异。2.各组大鼠肺内均可见凋亡细胞,CSE组AI较对照组明显增高(p<0.01)并且BQ123组和Bos组AI较CSE组明显减低(p均<0.01)但仍较对照组增高(p<0.01)。3.免疫组化及Western Blotting均提示caspase-3在CSE组的肺组织中表达明显增高,BQ123组和Bos组caspase-3的表达较CSE组明显降低,差异均有统计学意义(p均<0.05)。4.CSE组肺组织中MMP-2和MMP-9活性较对照组明显增高,ET受体拮抗剂干预能抑制增高的MMP-2和MMP-9活性(p均<0.05),而在BQ123组和Bos组之间无统计学意义。5.CSE组肺组织中TNF-α和IL-1β水平较对照组明显增高,ET-1拮抗剂干预组TNF-α和IL-1β水平较CSE组明显减低(p均<0.05)。所有大鼠肺组织中TNF-α和IL-1β浓度与肺泡间隔细胞AI呈正相关(r=0.693,r=0.555,p均<0.01)。6.CSE组大鼠血清抗氧化能力较对照组明显降低,ET-1拮抗剂干预后大鼠血清抗氧化能力较CSE组明显提高(p均<0.05)。结论1.腹腔内注射CSE能成功建立大鼠肺气肿模型。2.腹腔内注射CSE所致大鼠肺气肿模型存在肺泡间隔细胞凋亡、基质金属蛋白酶活性增高、气道炎症及氧化/抗氧化失衡。3.ET受体拮抗剂可部分抑制腹腔内注射CSE所致大鼠肺气肿模型肺内凋亡、增高的MMPs活性、气道炎症及氧化应激,最终改善腹腔内注射CSE所致大鼠肺气肿程度。4.ETA受体通过参与凋亡、蛋白酶失衡、慢性炎症及氧化应激在肺气肿病理机制中可能起着重要作用。第四章PGI2衍生物Beraprost在香烟提取物所致肺气肿模型中的保护作用及其机制研究目的观察PGI2衍生物贝拉司特(Beraprost,BPS)对CSE所致肺气肿的保护作用及其机制。方法将24只Sprague-Dawley大鼠按随机数字表法分为对照组、CSE组及低剂量BPS干预组(BPS-1组)和高剂量组(BPS-2组),每组各6只。CSE组和BPS组连续三周每周一次腹腔内注射CSE,此外BPS干预组连续三周每天胃管内给药BPS 100μg或200μg/kg/day。HE染色测定MLI和DI评估肺气肿程度。采用TUNEL检测凋亡并计算AI;采用免疫组织化学测定和Western blotting测定caspase-3在肺组织的表达;采用明胶酶谱法测定肺组织中MMP-2和MMP-9活性;采用ELISA测定肺组织中的6-keto-PGF1α、TNF-α、IL-1β和环磷酸腺苷(cAMP)的浓度;采用BAP试验检测大鼠血清抗氧化能力。结果1.3周后CSE组大鼠肺组织呈现肺气肿病理改变,不同剂量BPS干预组病理变化相对减轻。CSE组MLI和DI较对照组显著增高(p均<0.01)。BPS干预组MLI和DI较CSE组显著降低(p均<0.01),但两组间(BPS-1和BPS-2)无统计学差异。2.CSE组大鼠肺组织匀浆中6-keto-PGF1α水平较对照组明显降低,BPS干预组较CSE组明显增高(p均<0.05),BPS-2组较正常对照组和BPS-1组明显增高(p均<0.05)。3.各组大鼠肺内均可见凋亡细胞,CSE组AI较对照组明显增高(p<0.01),并且BPS-1组和BPS-2组AI较CSE组明显减低(p均<0.01)但仍较对照组增高(p<0.01)。4.免疫组化及Western Blotting均提示caspase-3在CSE组肺组织中表达明显增高,BPS干预组caspase-3的表达较CSE组明显降低,差异均有统计学意义(p<0.05)。5.CSE组肺组织中MMP-2和MMP-9活性较对照组明显增高(p均<0.05),不同剂量BPS均能抑制增高的MMP-2,差异有统计学意义(p均<0.05),不同剂量BPS能抑制增高的MMP-9活性,仅高剂量组有统计学意义(p<0.05)。而在BPS-1组和BPS-2组之间无统计学意义。6.CSE组肺组织中TNF-α和IL-1β水平较对照组明显增高(p均<0.05),BPS干预组TNF-α和IL-1β水平较CSE组明显减低,仅BPS-2组与CSE组比较有统计学意义(p均<0.05)。所有大鼠肺组织中TNF-α和IL-1β浓度与肺泡间隔细胞AI呈正相关(r=0.657,r=0.530,p均<0.01)。7.CSE组大鼠血清抗氧化能力较对照组明显降低,不同剂量BPS干预后大鼠抗氧化能力较CSE组明显提高(p均<0.05)。8.BPS-1组大鼠肺组织cAMP浓度为2.31±1.04μg/mg,BPS-2组cAMP浓度为3.83±2.83μg/mg,而正常对照组和CSE组检测不到cAMP浓度(<1.05μg/mg)。结论1.腹腔内注射CSE所致大鼠肺气肿模型存在肺泡间隔细胞凋亡、基质金属蛋白酶活性增高、气道炎症及氧化/抗氧化失衡。2.前列环素衍生物BPS在CSE诱导所致肺气肿模型中起着部分保护作用,其可能的机制是减轻凋亡,降低MMPs活性,减少炎症因子释放和增强血清抗氧化能力。3.BPS对肺气肿的保护作用无量效关系,高剂量BPS对肺气肿程度的改善并不优于低剂量组。

【Abstract】 Chapter 1 Evaluation of Endothelin-1 in patients with stable chronic obstuctive pulmonary diseaseObjectiveThe purpose of this study was to examine the levels of endothelin-1 (ET-1) in the bronchoalveolar lavage fluid(BALF),induced sputum and plasma in patients with stable chronic obstructive pulmonary disease (COPD) and to elucidate whether ET-1 is implicated in the pathological process of COPD.MethodsThirteen patients with COPD,14 healthy smokers and 14 normal controls were enrolled in the study.BALF and induced sputum were collected.Cells in BALF and sputum suspension were counted and classified with Wright’s stain.The ET-1 levels were measured by radioimmunoassay in all of samples.Results1.The differences of FEV1%pre,FEV1/FVC%and PEF between healthy smokers and normal controls weren’t significant(p>0.05). FEV1%pre,FEV1/FVC%and PEF in COPD patients were significantly lower than those in healthy smokers and normal controls(p<0.01).2.The total BALF and sputum cells in healthy smokers and patients with COPD were significantly higher than those in control group(p<0.01).In addition,the numbers of alvelor macrophages(AM) and neukocytes(PMN) in both healthy smokers and patients with COPD were significantly higher than those in control group(p<0.01).3.There wasn’t significant difference in the ET-1 levels in BALF of three groups(p>0.05).The sputum ET-1 levels in healthy smokers and patients with COPD were significantly higher than those in control group (p<0.05).The ET-1 levels in plasma in COPD patient were significantly higher than those in healthy smokers and control group(p<0.05).4.The numbers of AM were inversely correlated with FEV1%pre and FEV1%FVC(r=-0.480,p<0.01;r=-0.545,p<0.01) while the numbers of PMN were inversely correlated with FEV1%pre and FEV1%FVC(r=-0.677,p<0.01;r=-0.773,p<0.01) in patients with stable COPD.ET-1 levels in sputum and plasma were inversely correlated with FEV1%pre in stable COPD patients(r=-0.723,p<0.01;r=-0.801, p<0.01).In addition,the increase in sputum ET-1 levels was correlated with the increase of the AM numbers and plasma ET-1 levels(r=0.543,p<0.01;r=0.864,p<0.01).Conclusion1.There are chronic inflammatory process in airway of stable COPD and both PMN and AM contribute to the process.2.ET-1 may have a role in contributing to airway inflammation and airway remodeling in the pathological process of COPD.Chapter 2 The expression of prostacyclin is decreased in patients with stable chronic obstuctive pulmonary diseaseObjectiveTo investigate the expression of prostacyclin(PGI2) synthase (PGI2S) and 6-keto-PGF 1αthat is a production of endogenous PGI2 by non-enzymatic hydration in the supematants of lung homogenates in patients with stable COPD.MethodsThe lung tissues were obtained from 12 patients with stable COPD and 10 controls.The expression of PGI2S protein was assessed by immunohistochemistry using paraffin-embedded sections.Concentration of 6-keto-PGF1αwas measured by ELISA in the supernatants of lung homogenates.Sections were scored by a pathologist in blinded fashion for PGI2S staining and expressed as a ratio in small/medium blood vessels and airway epithelia.Results1.FEV1%pre and FEV1/FVC%in COPD patients were significantly lower than those in controls(p<0.01). 2.The differences in PGI2S staining were statistically significant in pulmonary small/medium-sized vessels and airway epithelia(p<0.05) between COPD patients and controls.3.The concentration of 6-keto-PGF1αin the supernatants of lung homogenates in COPD group was significantly lower than that of the control group[(2.6±0.4) vs(16.2±2.8) ng/ml,p<0.05].ConclusionsThe expression of PGI2 is decreased in COPD patients and PGI2 may be involved in the pathogenesis of COPDChapter3 Treatment with Endothelin-1 receptor antagonists prevents pulmonary emphysema in ratsObjectiveEndothelin(ET) is involved with physiologic functions related to respiratory system and seems to implicate the pathogenesis of pulmonary emphysema.We hypothesized that ET-1 plays an important role in the pathogenesis of emphysema and,thus the ET receptor antagonists may have protective role in the development of emphysema.MethodsSprague-Dawley rats(n=24) were divided into four groups:(1) control group,(2) cigarette smoke extract(CSE) group,(3) CSE+ BQ-123 group(a selective ETA receptor antagonist),and(4) CSE+ bosentan group(a mixed ETA/ETB receptor antagonist).CSE was injected intraperitoneally once a week for three weeks and BQ-123 and bosentan were administered daily for the same duration.Apoptosis index, caspase-3 activity,MMP-2 and MMP-9 activities and TNF-αand IL-1βconcentrations were measured in the lung tissues.Antioxidant activity were measured in the serums.Results1.We firstly confirmed the emphysematous destruction in the lungs of experimental rats induced by the intraperitoneal injection of CSE within 3 weeks.The MLI and DI were significantly increased in the CSE group(108.7±6.8μm and 62.2±7.0%,respectively) compared with control group(69.8±6.6μm,p<0.01 and 13.9±2.7%,p<0.01, respectively).However,the MLI and DI were significantly decreased in the BQ-123(89.0±7.4μm and 41.5%±4.5%,respectively) and bosentan groups(81.9±6.1μm and 44.0%μ8.5%,respectively) compared with CSE rats(p<0.01,respectively).2.The TUNEL-positive cells were markedly distributed in the peribronchioles,intra-alveoli,and septal areas of the emphysematous lungs in CSE rats comparing with the lungs of control rats.The AI was significantly higher in CSE group(20.3±0.9%) than control group(2.9±0.9%,p<0.01).And the AI was significantly reduced in BQ-123 group(9.9±2.3%,p<0.01) and bosentan group(8.8±0.6%,p<0.01) compared with that in CSE group.3.The caspase-3 positive cells were markedly distributed in the emphysematous lungs of CSE group comparing with the stained cells in the lungs of control rats.These positive cells were apparently reduced in the BQ-123 and bosentan groups compared with the stained cells in CSE group.Comparing with the control group,expression of caspase-3 was prominently enhanced in CSE groups,but almost no changes in both the BQ-123 and bosentan groups.The relative density of the caspase-3 toβ-actin by the densitometry analysis showed that the protein level of the cleaved caspase-3 was increased in the CSE rats(218.2±64.7%) compared with that in control rats(98.2±34.3%,p<0.05).Expectedly, both BQ-123 and bosentan treatments markedly inhabited the increases of the cleaved caspase-3 protein levels in rats injected with CSE (BQ-123:90.4±32.9%,Bosentan:84.9±30.8%,p<0.05 in comparison to CSE).4.Rats injected with CSE showed increased MMP-2 and MMP-9 activities in their lung tissue homogenates(MMP-2:172.1±43.5%; MMP-9:168.9±38.6%) compared with the activities in the control rats (MMP-2:105.5±27.1%,p<0.05;MMP-9:94.5±27.1%,p<0.05). Expectedly,MMP-2 and MMP-9 activities were reduced significantly in both BQ-123(MMP-2:109.6±32.8%,p<0.05;MMP-9:99.9±50.0%, p<0.05) and bosentan groups(MMP-2:95.1±14.1%,p<0.01; MMP-9:68.4±19.9%,p<0.01) compared with the activities in the CSE group.5.The levels of TNF-αand IL-1βwere significantly increased in the CSE group in comparison to those in controls(p<0.05, respectively).BQ-123 and bosentan significantly prevented the increases of the levels of TNF-αand IL-1βin lungs of rats with injection of CES (p<0.05).In addition,the levels of TNF-αand IL-1βin the lungs were positively correlated with the AI in the lungs of rats(r=0.693,p<0.01; r=0.555,p<0.01,respectively).6.The serum antioxidant activity was significantly decreased in the CSE group(1653.4±504.7μmol/L) in comparison to that of controls (2438.9±235.6μmol/L,p<0.01).The BQ-123 and bosentan significantly prevented the decrease of the serum antioxidant activity in the rats injected with CSE(BQ123:2551.1±144.8μmol/L,p<0.01; Bosentan:2597.0±409.8μmol/L,p<0.01).ConclusionET-1 receptor antagonists protect against the development of emphysema probably by decelerating apoptosis,inhibiting proteolytic enzyme activity,reducing inflammatory cytokine levels and improving antioxidant activity.ET-1 antagonists may represent a new therapeutic option in the treatment of emphysema in humans.Chapter 4 A novel protective effect of a prostacyclin analogue in the development of cigarette smoke extract-induced emphysemaObjectiveThe aim of this study was to determine whether the administration of PGI2 analogue,beraprost(BPS) would attenuate the development of CSE-induced emphysema in a rat model and,further,to elucidate the molecular mechanisms involved with its effect.Methods Sprague-Dawley rats(n=24) were randomly divided into 4 groups:normal group,CSE group,low dose BPS group(BPS-1) and high dose BPS group(BPS-2).The CSE-PBS solution was injected intraperitoneally with 1 ml once a week.BPS was administered daily via a gastric gavage for 21 days.BPS was started at the day of the first CSE injection.TUNEL was performed to observe the DNA damaged cells and the expression of caspase-3 was determined by immunohistochemistry and Western Blotting.MMP-2 and MMP-9 activities were investigated by gelatin zymography and TNF-αand IL-1βconcentrations were measured by ELISA.We also analyze the serum antioxidant activity by bioantioxidant power(BAP) test.Results1.We confirmed that intraperitoneal injection of CSE in rats caused emphysematous destruction of the lung within 3 weeks.The MLI and DI were significantly increased in the CSE group compared with the values in the control group(MLI:108.7±6.8μm vs.69.8±6.6μm,p<0.01 and DI:62.2±7.0%vs.13.9±2.7%,p<0.01,respectively).The MLI and DI were significantly reduced in the lungs in the BPS-1 group(MLI: 83.9±10.5μm,p<0.01;DI:49.3±7.5%,p<0.01) and BPS-2 group (MLI:77.0±7.1μm,p<0.01;DI:47.1±6.9%,p<0.01) compared with those in the CSE group.2.The concentration of 6-keto-PGF1αwas significantly reduced in the lung tissues of the rats with CSE-induced emphysema(40.6±29.3μg/mg) compared with those of control rats(173.2±49.3μg/mg,p<0.01).BPS treatment markedly increased the level of 6-keto-PGF1αcompared with that in CSE injected rats(BPS-1:134.4±52.1μg/mg,p<0.05;BPS-2:432.9±71.5μg/mg,p<0.01).It is curious that the 6-keto-PGF1αlevel in high-dose BPS group was three-folds higher than that in groups of control and low-dose BPS rats(p<0.01).3.The TUNEL-positive(TUNEL+) cells were frequently localized in the peribronchiolar,intra-alveolar,and septal structures in the CSE-injected rats.The DNA damaged cells were very rare in the normal rats(AI:2.9±0.9%),while the TUNEL+ cells in CSE group were much more frequent(AI:20.3±0.9%,p<0.01).BPS greatly reduced the number of TUNEL+ cells in the lungs of CSE treated emphysematous rats(AI:8.9±2.5%in BPS-1 group and 7.8±1.3%in BPS-2 group,p<0.01 vs.controls for each).4.Rats injected with CSE showed a large number of caspase-3+ alveolar septal cells compared with the cells in the control and BPS treated rats.The protein levels of the cleaved form of caspase-3 were increased in the rats with CSE-induced emphysema(270.1±34.7%) compared with those of control rats(146.3±20.4%,p<0.05).BPS treatment markedly reduced the protein level of cleaved caspase-3 compared with that in CSE injected rats(BPS-1:162.7±53.3%,p<0.05;BPS-2:154.0±32.8%,p<0.05).5.Rats injected with CSE showed increased MMP-2 and MMP-9 activities in their lung tissue homogenates(MMP-2:215.2±33.5%,p<0.01;MMP-9:190.5±60.0%,p<0.05) compared with the activity in the control rats(MMP-2:98.2±38.4%,MMP-9:84.1±29%).MMP-2 and MMP-9 activities were reduced in the two BPS treatment groups, but statistical significance occurred in MMP-2 activity of both low- and high-dose BPS treatment rats(BPS-1:148.1±45.3%,p<0.05;BPS-2: 116.8<53.3%,p<0.01,respectively) while in MMP-9 activity in only high dose BPS treatment rats(97.3±40.6%,p<0.05).6.The levels of TNF-αand IL-1βwere significantly increased in the CSE group compared with those in controls(p<0.01).And high-dose BPS was significantly reduced the levels of TNF-αand IL-1βin the lungs of CSE treated emphysematous rats(p<0.01).The levels of TNF-αand IL-1βwere positively correlated with the AI in the lungs of all rats including the control rats and emphysema rats induced by CSE injection(r=0.657,p<0.01 and r=0.530,p<0.01,respectively).7.The serum antioxidant activity was significantly decreased in the CSE treated rats(1653.4±504.7μmol/L,p<0.05) compared with the control rats(2438.9±235.6μmol/L).BPS treatment significantly prevented the reduction of antioxidant activity in rats injected with CSE (BPS-1:2420±434.4μmol/L,p<0.05,BPS-2:2344.8±664.6μmol/L, p<0.05,in comparison to CSE group). 8.The cAMP levels were 2.31±1.04μg/mg in the lung tissues of BPS-1 group and 3.83±2.83μg/mg in BPS-2 group,in contrast to the undetectable cAMP levels in both the control rats and CSE-injected rats (less than 1.05μg/mg).ConclusionBPS protects against the development of CSE-induced emphysema by attenuating apoptosis,inhibiting proteolytic enzyme activity, reducing inflammatory cytokine levels and augmenting antioxidant activity.BPS may potentially represent a new therapeutic option in the prevention of emphysema in humans in prospect.

  • 【网络出版投稿人】 中南大学
  • 【网络出版年期】2010年 02期
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