Neonatal meconium aspiration syndrome (MAS) can be treated by exogenous surfactant (S). However, aspirated meconium initiates local inflammation and oxidation which may inactivate surfactant and reduce its action. This experimental study estimated whether combined use of surfactant and the antioxidant N-acetylcysteine (NAC) can enhance effectiveness of therapy. Meconium-instilled rabbits were non-treated (M), treated with monotherapies (M + S, M + NAC), combined therapy (M + S + NAC), or received saline instead of meconium (controls, C). Surfactant therapy consisted of two lung lavages (BAL) with diluted Curosurf (5 mg phospholipids/ml, 10 ml/kg) followed by undiluted Curosurf (100 mg phospholipids/kg). N-acetylcysteine (Acc Injekt, 10 mg/kg) was given intravenously in M + S + NAC group 10 min after surfactant therapy. Animals were oxygen-ventilated for additional 5 h. Then, differential white cell count in the blood (WBC) was determined. Left lung was saline-lavaged and differential cell count in BAL was determined. In right lung tissue, wet/dry weight ratio, oxidation markers (TBARS, 3NT) and interleukines (IL-2, IL-6, IL-13, and TNFα) using ELISA and RT-PCR were estimated. Combined S + NAC therapy significantly decreased W/D ratio, TBARS, 3NT, and IL, whereas the effect of monotherapies (either S or NAC) was less obvious. In conclusion, addition of NAC to surfactant treatment may enhance the therapeutic outcome in MAS.
Keywords: Antioxidant; Inflammation; Meconium aspiration syndrome; N-Acetylcysteine; Oxidative damage; Surfactant.