【摘要】 目的探讨新生大鼠急性肺损伤的病理特点及其机制。方法采用腹腔注射内毒素(LPS,5mg/kg)的方法制备新生和成年Wistar大鼠急性肺损伤动物模型,在光镜和电镜下观察肺的病理改变,用ELISA、RT PCR法检测肺组织TNFα蛋白和mRNA的表达。结果LPS注射后1h,大体、光镜和电镜下可见新生大鼠明显的肺出血现象,内皮细胞、肺泡上皮细胞和基底膜损伤明显,可见粒细胞浸润,上述改变随LPS作用时程延长加重;而成年大鼠以肺水肿、大量粒细胞浸润为主。与成年大鼠相似,LPS注射后lh新生大鼠肺湿/干重比(W/D),肺组织髓过氧化物酶(MPO)活性和TNFα蛋白含量均明显增高;支气管肺泡灌洗液(BALF)中多形核粒细胞(PMN%)于2h时明显增高,肺组织TNFαmRNA的表达于0.5h时即显著增高。结论与成年大鼠不同,LPS5mg/kg腹腔注射后,新生大鼠主要表现肺出血,并可引起肺部过度的炎症反应。更多还原

【Abstract】 Objective To compare pathological characteristics of acute lung injury in neonatal and adult rats.Methods Lung injury models in neonatal and adult rats were established via intraperitoneal injection of 5 mg/kg lipopolysaccharides (LPS) . The pathological changes were observed under microscopy and electron microscope. The tumor necrosis factor-α (TNF-α) protein level and mRNA expression were measured by ELISA and RT-PCR.Results One hour following LPS administration to neonatal rats, lung hemorrage was observed; under microscope and EM, obvious injuries in endothelial cells, alveolar cells and basement membrane were observed accompanied with polymorphonuclear neutrophil infiltration.These changes aggravated with time after LPS administration; whereas adult rats manifested mainly edema with large polymorphonuclear neutrophil infiltration in the lung. Wet/dry ratio, lung tissue myeloperoxidase activity, TNF-α protein in neonatal rats at l hour after LPS were significantly increased.After two hours, PMN percentage in BALF increased extensively;after 30 minutes, TNF-α mRNA level increased. Conclusion LPS (5 mg/kg) administration to neonatal rats results in lung hemorrhage accompanied by exaggerated-inflammatory responses.更多还原