褪黑素对烟雾吸入所致大鼠急性肺损伤的保护作用

目的通过建立褪黑素干预大鼠烟雾吸入性损伤模型,探讨褪黑素对急性肺损伤的保护作用。方法成年清洁级雄性SD大鼠72只随机分为空白组、损伤组和褪黑素组。空白组不做任何处理,损伤组于吸入性损伤处理后腹腔注射1%乙醇生理盐水（10ml/kg）,褪黑素组于吸入性损伤处理后腹腔注射褪黑素（10mg/kg,1次/8h）。三组大鼠分别在3h、12h、24h三个时相腹主动脉取血2ml后处死,动脉血离心后检测肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）含量和白细胞介素10（IL-10）。肺组织匀浆测超氧化物歧化酶（SOD）、丙二醛（MDA）、髓过氧化物酶（MPO）的含量。取右下肺组织作病理切片,光镜下观察肺组织病理情况。结果光镜下见空白组大鼠肺泡腔结构完整,壁光滑;损伤组肺泡壁增厚,肺间质炎症细胞浸润;褪黑素组肺组织较损伤组病理表现有所减轻。褪黑素组各时相点血清TNF-α和IL-6含量高于空白组（P〈0.05）,低于损伤组（P〈0.05）。损伤组各时相点IL-10含量与空白组相比无统计学差异（P〉0.05）,而褪黑素组IL-10含量与空白组、损伤组相比均升高（P〈0.05）。褪黑素组各时相点肺组织SOD含量均高于损伤组（P〈0.05）,低于空白组（P〈0.05）。褪黑素组各时相肺组织MDA和MPO含量均高于空白组（P〈0.05）,低于损伤组（P〈0.05）。结论褪黑素可以减轻炎症及氧化应激,对烟雾吸入性损伤所致急性肺损伤发挥一定的保护作用。

Protective effects of melatonin on acute lung injury induced by smoke inhalation injury in rats

Objective To investigate the protective effects of melatonin on acute lung injury induced by smoke inhalation injury in rats.Method Seventy-two rats were randomly divided into control group,injury group and melatonin group. The control group were received no treatment. The injury group were administered i.p.1% ethanol saline（10 ml/kg）. The melatonin group were administered i.p. melatonin （10 mg/kg, q8h）immediately after inhalation injury. Abdominal aortic blood of all rats was collected at 3 h, 12 h, 24 h three-phase. Then they were all decapitated and lung tissues were collected. Serums were prepared for detection of tumor necrosis factor α（TNF-α）, interleukin 6（IL-6）and interleukin 10（IL-10）.Lung homogenates were examined for superoxide dismutase （SOD）,malondialdehyde （MDA） and myeloperoxidase （MPO）. The pathological changes in lungs were also examined under an optical microscope.Results Under the microscope, compared with control group, lungs of injury group and melatonin group were observed to have infiltrating inflammatory granulocytes, diffused alveolar septum thickening. The pathological change of lung in melatonin group was minimal in comparison to injury group. Compared with control group, levels of TNF-α and IL-6 were higher in melatonin group and injury group. The TNF-α and IL-6 levels of melatonin group were lower than those of the injury group. The IL-10 levels of injury group had no significant difference with that of control group, the IL-10 level of melatonin group was higher than that of control group and injury groupCompared with control group,levels of MDA and MPO were higher in melatonin group and injury group, the MDA and MPO levels of melatonin group were lower than injury group.Compared with control group, the SOD levels were lower in melatonin group and injury group.The SOD levels of melatonin group were higher than injury group. Conclusion Melatonin can reduce inflammatory response and oxidative stress,and have some protective effects on acute lung injury induced by smoke inhalation injury.