Levels Of Transforming Growth Factor-β1,Surfactant Protein A And D In Meconium Aspiration Syndrome In Newborns

Objective: Meconium aspiration syndrome(MAS) is from the embryo apnea because of the oxygen deficiency in the uterus, the anus sphincter dilatated, discharged the meconium-stained amniotic fluid. When prior to delivery or delivery, meconium inspiration to lungs caused a series of clinical manifestation, remaines a relevant cause of neonatal respiratory failure.MAS mainly occurred in full-term, smaller than the gestational age and post-term infants. In the domestic report, MAS occurred in live-born infants approximately 1.2%-2.2%, case fatality rate approximately 7%-15.2%. The hypoxemia, high carbohemia and the acidosis were clinanical characteristic, and the case fatality rate was high. Meconium entered into the lung, induced the serious inflammation responses in bronchiole and the pulmonary alveolus and caused many kinds of cytokine to release. Meconium aspiration is characterised by severe atelectasis, the influx of neutrophils, edema, and hyaline membranes.Meconium contains cholesterol, free fatty acids and bilirubin all of which can interfere with surfactant function in a dose-dependent fashion. Providing amounts of surfactant can overcome some of this inhibition.Meconium aspiration treated with surfactant have improved histology, lung mechanics and gas exchange. This experiment was for the purpose of observing how exogenous pulmonary surfactant influenced the concentration of SP-A,SP-D and TGF-β1 both in blood serum and bronchoalveolar lavage fluid, and lung function such as oxygenation and gas exchange function of infants troubled with MAS, thus provided the theory basis for the therapy of MAS.Methods:The newborns of the intensive care unit in Hebei Province children hospital were selected, who entered newborn department on June, 2007 to January, 2009, were consistent with the MAS diagnostic criteria , and except congenital broncho-pulmonary dysplasia, congenital diaphragmatic hernia and congenital heart disease, 45 of them were selected. The patients were randomized in a non-blinded manner to receive either PS (A group, n=22) or no PS (the conventional therapy group, B group,n=23). All of them were given tracheal intubation, irrigation of trachea, mechanical ventilation, and intravenous drip antibiotics and keep water-electrolyte balance, et al.At the same time, group A accepted PS.Group A were taken the bronchial alveolus fluid and the venous blood 2ml when accepted PS treatment (0h) was received and 24 hours (24h), 48 hours (48h) after. With the 3000r/min centrifugalization 10 minutes, the supernatant and blood serum stored at -30℃refrigerator for subsequent analysis. Group B were taken the bronchial alveolus fluid and the venous blood 2ml when machine ventilation treatment were received 0h,24h and 48h aftter. With the 3000r/min centrifugalization 10 minutes, the supernatant and blood serum stored at -30℃refrigerator for subsequent analysis. Arterial blood gas tensions, Parameters of fraction of inspired oxygen (FiO2), OI, mortality, ventilation time, were recorded. The concentration of SP-A,SP-D and TGF-β1 in the bronchial alveolus fluid and the venous blood detected by enzyme- linked immunosorbent assay (ELISA) technique.The statistical analysis SPSS10.0 statistics software was used to carry on statistics processing, P<0.05(double side) had statistical significance.Results:1 There was no statistical difference among the two groups for gestational age, birth weight, postnatal age, delivery mode and sex distribution (P>0.05).2 The time of mechanical ventilation of group A, B was 71.08±6.14h, 113.62±21.39h, oxygen time was 130.62±20.31h,148.61±21.52h,group A was more lower than group B, there was significantly statistical difference between them(P <0.05).There were no significant difference of OI, a/APO2 on 0h between group A and group B, But OI of group A was lower than group B on 24h and 48h. a/APO2 was higher than group B on 24h and 48h. There was significant difference(P<0.05).3 Comparison of prognosis and turnover indicated that there were no statistical difference of incidence rate of frequent hemorrhoid, pneumonorrhagia, ICH(Ⅱ-Ⅳ)between group A and group B,but there was significant difference of mortality between the two groups.4 Compared with group B, SP-A,SP-D,TGF-β1 in blood serum of group A on 0h,there were no significant differences between the two groups. On 24 hours after therapy, compared with group B, SP-A,SP-D,TGF-β1 in blood serum of group A were lower,but not TGF-β1 had significant differences. On 48 hours, SP-A,SP-D,TGF-β1 in blood serum of group A were lower than group B,and all of them had statistical differences. (P<0.05).There were no statistical differences between group A and group B of SP-A,SP-D and TGF-β1 in bronchial alveolus fluid on 0h.Compared with group B, SP-A,SP-D in group A of bronchial alveolus fluid were increased on 24 hours after therapy,while TGF-β1 was lower,there was significant differences between them.The result on 48 hours after therapy was just the same as the result on 24hours.In statistics had significance differences(P<0.05).Conclusions: 1 The beneficial effects of replacement of pulmonary surfactant in routine dose on meconium aspiration syndrome may be due to exogenous surfactant could stimulate endogenous surfactant secretion,both SP-A and SP-D increased. 2 The beneficial effects of replacement of pulmonary surfactant in routine dose on meconium aspiration syndrome may inhibit the release of transforming growth factor-β1, relieve the inhibition of pulmonary surfactant, restrain lung injury. 3 The replacement of pulmonary surfactant overcome the inhibition of meconium,improve the oxygenation,gas exchange and shorten the ventilation time and hospital stay without augmentation of risk of pulmonary hemorrhage ,IVH and pneumothorax in these neonatal patients.