地塞米松对海水淹溺性肺损伤兔肺组织炎症反应的抑制作用

The inhibitory effects of dexamethasone on inflammatory responses in the lung tissue of rabbits with acute lung injury induced by seawater drowning

目的了解地塞米松对海水淹溺性肺损伤兔肺组织炎症反应的影响。方法机械通气的麻醉新西兰兔随机分成对照组(CG)和地塞米松治疗组(DG),每组12只。CG兔的气管内灌注4 mL／kg体重海水,DG兔在CG的基础上静注1 mg/kg地塞米松。取部分右下肺行常规病理学检查。分别用RT-PCR和ELISA检测肺组织中TNF-α、IL-1β和IL-8的mRNA表达及蛋白含量。结果病理学观察显示CG的肺组织内有大量的炎性细胞浸润,肺泡腔内有出血及透明膜形成。DG的上述改变轻于CG。DG肺组织内TNF-α、IL-1β和IL-8的mRNA表达及蛋白含量显著低于CG(P<0．05)。结论地塞米松治疗可抑制海水淹溺性肺损伤兔肺组织TNF-α、IL-1β和IL-8的表达,减轻肺组织内炎症反应。

Objective To investigate the effect of dexamethasone on inflammatory responses in the lung tissue of rabbits with acute lung injury induced by seawater drowning. Methods Seawater （4 ml/kg body weight） was instilled into the lower trachea of ventilated, anesthetized rabbits. Then 20 minutes later, these rabbits were assigned randomly to receive intravenous injection of 1 mg/kg body weight of dexamethasone （ designated as dexamethasone treatment group, DG, n = 12） or 2 ml of normal saline （ control group, CG, n = 12）. A portion of right lower lung was prepared for light microscopic examination. Expressions of TNF-α, IL- 1β and IL-8 mRNA in lung tissue were measured by reverse transcriptase-polymerase chain reaction （RT- PCR） , and concentrations of proteins were detected by ELISA. Results Light microscopic finding in the CG demonstrated a marked lung injury, represented by hemorrhage, edema, thickened alveolar septum, formation of hyaline membranes and the infiltration of inflammatory cells in alveolar spaces. In the DG, these changes were less pronounced. The DG＇s TNF-α, IL-1 β and IL-8 mRNA and protein were significantly lower than those in the CG. Conclusions Dxamethasone can inhibit the expressions of TNF-α, IL-1β and IL-8, and relieve the inflammatory responses in the lung tissue of rabbits with acute lung injury induced by seawater drowning.