| Pulmonary maturity is closely related to gestational age.Neonatal respiratory distress syndrome?NRDS?is the first place in premature infant morbidity and mortality due to poor lung development and lack of pulmonary surfactant?PS?.Therefore,it is very important for preterm birth risk of pregnant women and early preterm infants to promote lung maturation.A large number of studies have confirmed that perinatal use of glucocorticoids?glucocorticoid,GC?can promote lung maturation,but the cardiovascular,metabolic and neuroendocrine system functions may have long-term adverse effects.Therefore,the current guidelines have strict limits on the use of GC for pregnant women and premature infants at risk of premature birth[1].Budesonide?BUD?aerosols are a kind of inhaled GC,which is used as a potent antiinflammatory drug in the treatment of respiratory diseases.At the beginning of this century,several multicenter studies have shown that early inhalation of BUD in preterm infants has the same effect as intravenous dexamethasone?DXM?,which can also effectively improve pulmonary function?PF?[2,3].The latest study shows that tracheal instillation of BUD is mainly distributed in the lung tissue,which is very small in blood and does not enter the brain tissue[4],and there is little possibility of dysplasia cause the nervous system development.This shows that intratracheal BUD may be a new method of promoting lung maturation more safely than the use of DXM.However,the effect of intratracheal BUD on lung development in premature infants is unclear.Therefore,we studied the effects of intravesical BUD on alveolar morphology and PS system in premature rabbits.Meanwhile,the effect of exogenous PS on the effect of BUD on lung maturation was also discussed.method:Fetal rabbits were taken out from female rabbits on the 28th day of pregnancy?with the full term of 31 days?by cesarean section?c-section?.The fetal rabbits were divided into four groups:control?normal saline,NS?,budesonide?budesonide,BUD?,calf pulmonary surfactant for injection?pulmonary surfactant,PS?,and calf pulmonary surfactant+budesonide for injection?pulmonary surfactant+budesonide,PS+BUD?.Each group of 6 fetal rabbits,after 1-hour tracheal administration,then gastric tube over10%chloral hydrate,take the lung tissue reserve.1.Make the lung tissue and HE staining slices.The pathological changes of lung tissue were observed under light microscope,including alveolar morphology,transparent membrane,edema of lung tissue and inflammatory cell exudation.Image-Pro Plus 6.0image analysis software was used to analyze these images.The alveolar wall thickness,alveolar radius and alveolar area were measured.2.Electron microscopy ultra-thin sliced lung tissue,were observed under tem premature rabbit lung tissue ultrastructure changes.The alveolar type ? epithelial cells?AT ??,lamellar bodies?LB?,mitochondria and glycogen granules were observed.3.The relative expression of SP-B mRNA in lung tissue of rabbits was detected by RT-PCR.4.The expression of SP-B protein in lung tissue of preterm fetal rabbits was detected by Western blotting using Western blotting?Western blotting?5.Statistical analysis:Data were analyzed using SPSS version 19.0 statistical software?SPSS,IL,USA?.The results were expressed as`x±s.The single-factor variance analysis or variance analysis of repeated measurements was used for comparison among groups.The t test was used for comparisons between two groups at a time.A P value less than 0.05 means that the difference was statistically significant.result:1.Alveolar morphological changes:light microscope can be seen in the BUD group atelectasis than the NS group to reduce the formation of alveolar cavity,part of the alveolar wall has a transparent film formation,lung tissue edema than the control group to reduce,showing a small amount of inflammatory cell oozing;There was no obvious pulmonary atrophy in the PS group.There was no obvious pulmonary edema and inflammatory cell exudation.There was no pulmonary atelectasis in the PS+BUD group,the alveolar cavity increased evenly and the alveolar septum became thin,No obvious transparent film formation,no obvious pulmonary edema and inflammatory cell exudation.?18.78±5.64?m?,alveolar radius?62.26±19.73mm?and alveolar area?6224.17±1399.53m2?in the control group,the alveolar wall thickness?10.39±2.07mm?in the BUD group was significantly higher than that in the NS control group?P<0.01?.The alveolar radius?89.00±11.21?m?in the BUD group was significantly higher than that in the NS control group?P<0.01?,and the alveolar area?10997.60±1790.76 m?in the BUD group was significantly higher than that in the NS control group?P<0.01?.The alveolar wall thickness?7.65±1.42?m?in the PS group was significantly thinner than that of the NS control group?P<0.01?,and the alveolar radius of the PS group?117.70±28.67?m??P<0.01?.The alveolar area of PS+BUD group?5.84±1.30?m?was significantly higher than that of NS control group?P<0.01?.The alveolar radius of PS+BUD group?159.96±24.57?m?was significantly higher than that of NS control group?P<0.01?,and the alveolar area of PS+BUD group?19739.17±2553.69mm2?compared with NS control group was significantly increased?P<0.01?;2.The changes of AT ? and LB were observed under transmission electron microscope.The swelling of AT ? was observed in NS group,while the number of LB was sparse.The swelling of AT ? was observed in BUD group,but the number of LB was more than that of control group The density and the deep staining were observed.In PS+BUD group,AT?was normal and contained glycogen granules.LB matured and separated from the cells and entered the interstitial cells.The optical density?OD?of the NS group was 0.23±0.16,the OD value of the BUD group was 0.35±0.12,the OD value of the PS group was 0.55±0.12,and the OD value of the PS group was 0.55±0.12,0.28,the OD value of LB in PS+BUD group was 0.85±0.33,suggesting that early postnatal tracheal instillation of BUD can increase the rabbit's OD value of LB?P<0.05?;3.The expression of SP-B mRNA in fetal lung tissue was significantly higher than that in control group?P<0.05?.The expression of SP-B mRNA in fetal lung tissue was significantly higher than that in control group 1.00±0.13?P<0.05?.The relative expression of SP-B mRNA in PS group was 1.80±0.12?P<0.05?.The expression of SP-B mRNA in PS+BUD group was 1.53±0.07?P<0.05?The relative expression was2.00±0.09?P<0.05?.4.The relative abundance of NS control group was 1.00±0.06,the relative abundance of BUD group was 1.28±0.12?P<0.05?,and the relative abundance of PS group was 1.89±0.20?P<0.05?.The relative abundance of PS+BUD group was 2.28±0.17?P<0.05?.conclusion:1.BUD tracheal instillation can effectively promote premature fetal rabbit alveolar development;2.BUD tracheal instillation can promote the maturity of PS system;3.BUD tracheal instillation can effectively reduce the alveolar surface tension;4.BUD combined tracheal intratracheal instillation of lung-promoting role is better than the two alone. |
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