Aim: 

Anti-inflammatory treatment may diminish lung oedema, inflammation, airway hyperreactivity, and pulmonary vasoconstriction associated with meconium aspiration, and thereby improve lung functions.

Methods: 

Air-ventilated adult rabbits intratracheally received 4ml/kg of saline (Sal group, n = 5) or meconium suspension (25mg/ml). From this moment, all animals were oxygen-ventilated. When respiratory failure developed, meconium-instilled rabbits received dexamethasone (0.5mg/kg, Mec+Dex group, n = 8), aminophylline (2.0mg/kg, Mec+Amin group, n = 7) i.v., or budesonide (0.25mg/ kg, Mec+Bud group, n = 8) intratracheally by inpulsion effect of high-frequency jet ventilation at two doses 0.5 and 2.5h after meconium instillation, or were left without treatment (Mec group, n = 8). Animals were oxygen-ventilated for additional 5h after the first treatment dose. Respiratory parameters, blood gases and white blood cells count (WBC) were evaluated regularly. Post mortem, in vitro airway reactivity was measured in tracheal and right lung strips, lung oedema was determined by wet/dry weight ratio, and markers of lipid and protein oxidation were estimated in lung homogenate. Left lungs were saline-lavaged and differential WBC was calculated in BAL sediment.

Results: 

Treatment with Dex, Amin and Bud significantly improved gas exchange, decreased pulmonary shunting, central venous pressure, ventilatory pressures, reduced meconium-induced lung oedema, airway hyperreactivity, neutrophil count in BAL associated with higher WBC and neutrophils in blood, and diminished oxidative modifications of proteins and lipids in lung homogenate compared to non-treated Mec group (all P < 0.05, 0.01 or 0.001). Conclusion:

Anti-inflammatory treatment effectively improved the lung functions in meconium-instilled rabbits. Supported by Grant of VEGA 1/2306/05.