褪黑素对哮喘大鼠肺组织活性氧产生的影响(英文)

Effect of melatonin on reactive oxygen species in rats with asthma

摘要:

目的 支气管哮喘是慢性气道炎症性疾病 ,肺组织活性氧产生可以导致气道炎症 ,本研究目的探讨褪黑素 (MT)对哮喘模型大鼠肺组织活性氧 (ROS)生成以及气道炎症的影响。方法 将 2 4只大鼠随机分为 3组 :哮喘组 (n=8) :用 10 %鸡卵白蛋白 (OVA) 1ml、氢氧化铝凝胶 10 0mg无菌腹腔注入 ,2周后用 1%OVA超声雾化吸入 2 0min ,连续激发 1周致其哮喘发作 ;MT组 (n =8) :模型制作同哮喘组 ,在每次激发前 30min腹腔注入MT 10mg/kg ;对照组 (n =8) :以生理盐水代替OVA吸入。每组分别于最后一次激发后 6h测定气道反应性 ;取支气管肺泡灌洗液 (BALF)进行白细胞计数、分类 ;取肺组织进行活性氧产量测定。结果 MT组大鼠气道反应性及BALF中炎性细胞数明显低于哮喘组 ,差异有显著性 (P <0 .0 5 )。肺组织活性氧产量在哮喘组、MT组及对照组分别为 (114 .8± 11.3)U/mgprot、(95 .2± 5 .9)U/mgprot及 (87.5± 7.4 )U/mgprot,哮喘组高于其它两组 ,差异均有显著性 (P <0 .0 5 )。结论 哮喘组大鼠肺组织活性氧产量增加。MT干预可以降低肺组织活性氧产生 ,降低气道炎症和气道高反应性 ,这可能是其治疗哮喘的保护机制。

Abstract:

Objective Asthma is recognized as a chronic airway inflammatory disease. Reactive oxygen species can induce airway inflammation. The aim of this study was to explore the effect of melatonin (MT) on the content of reactive oxygen species and airway inflammation in rats with bronchial asthma. Methods Twenty-four Sprague-Dawley (SD) rats were randomly assigned into 3 experimental groups (8 in each): 1) Asthma group: the rats were immunized on day 1 by intraperitoneal injection of 100 mg ovalbumin (OVA) in 1 ml saline with 100 mg of aluminum hydroxide. After 14 days, the rats were challenged with aerosolized 1% OVA for 20 mins per day for 7 consecutive days; 2) MT group: OVA-sensitized rats were given intraperitoneal injection of 10 mg/kg MT 30 mins before each OVA challenge; and 3) Control group: OVA was replaced with normal saline. Airway responsiveness to aerosolized acetylcholine was detected 6 hrs after the last challenge. Then the rats were lavaged and total and differentiated leukocytes counts in bronchoalveolar lavage fluid (BALF) were performed after Wright-Giemsa staining. At the same time, the content of reactive oxygen species (ROS) in the lung tissues was assessed with chemical colorimetry. Results After OVA challenge, there was a significant decrease in airway responsiveness and the number of lymphocytes and eosinophils in the BALF of the MT group compared with the Asthma group (P< 0.05). The MT group also showed a significantly lower ROS level in the lung tissues compared with Asthma group (P< 0.05). Conclusions MT can decrease airway inflammation and the content of ROS in asthmatic rats, which may be the underlying protective mechanisms of MT against asthma.