| Objective In recent years,with the continuous advancement of modern medical technology and the establishment of neonatal intensive care units,the premature infants with smaller gestational age and lower body weight have survived,accompanied increasing incidence of comorbidities.Bronchopulmonary dysplasia(BPD)is one of the common complications of respiratory system in premature infants,and its incidence was increasing year by year.The lung function of children with BPD was obviously impaired,the oxygen inhalation time is long after birth,Can’t be separated from oxygen,and the incidence of respiratory diseases and rehospitalization rate are higher than those of non-BPD patients,which was seriously threatened the survival rate of surviving preterm infants and the quality of life in the long term.At present,it is believed that multi-factor and multi-gene cause BPD,that is,high-oxygen inhalation,barotrauma,volume injury,infection,inflammation and other unfavorable factors act on the genetic susceptibility of children,which was impaired immature lung tissue,as well as abnormal repair of lung tissue.But so far,the exact pathogenesis of BPD is still unclear.MicroRNAs(miRNAs)are non-coding RNAs that are ubiquitous in eukaryotic cells and consist of 21-25 nucleotides.In recent years,the abnormal expression and regulation of miRNAs in the pathogenesis of BPD was attracted much attention.MicroRNA-21(miRNA-21)is a kind of miRNA.Studies was show that miRNA-21 plays an important role in the development and development of lung tissue.A number of studies abroad have shown that the expression of miRNA-21 is up-regulated in the rat BPD model.MicroRNA-21-5p(microRNA-21-5p,miRNA-21-5p)is one of the miRNA-21 molecules.It is currently believed that miRNA-21-5p is also involved in the pathogenesis of BPD,but the expression level and regulation mechanism of miRNA-21-5p in BPD lung tissue was not clear and need further exploration.In this study,we established a BPD model of neonatal SD rats induced by hyperoxia to investigate the expression of miRNA-21-5p in lung tissue of BPD rats.Methods Sixty new Sprague Dawley(SD)rats were randomly divided into hyperoxia group and control group,30 rats in each group.Rats in the hyperoxia group were placed in a closed oxygen chamber(90% oxygen concentration)for the preparation of a neonatal rat BPD model,and the control group was placed in normal air(oxygen concentration 21%).on the 1st,4th,and 7th day after birth,the lung tissue of the rats was taken out.The right lung and lung tissues were used for HE staining.The pathological changes of lung tissue were observed under light microscope.The alveolar diameter,alveolar cavity area and RAC changes were compared between the two groups.The left lung was used to detect the relative expression of miR-21-5p by quantitative Real-time PCR(qRT-PCR).Results The alveolar diameter,alveolar section area,RAC and miRNA-21-5p relative expression were compared between the two groups on the 1st day.The difference was not statistically significant(P>0.05).In the hyperoxia group with the increase of age,the alveolar diameter and the alveolar cavity area increased,the RAC decreased gradually and the expression of miRNA-21-5p decreased.The difference was statistically significant on the 4th,7th compared to 1st day(P<0.05).In the control group with the increase of age,the alveolar diameter and the alveolar cavity area decreased,the RAC increased and the expression of miRNA-21-5p increased.The difference was statistically significant on the 4th,7th compared to 1st day(P<0.05).The two groups were compared to the relative expression of alveolar diameter,alveolar cavity area,RAC and miRNA-21-5p on the 4th and 7th day.The differences were statistically significant(P<0.05).Conclusion The BPD model can be successfully established after 7 days of continuous high-concentration oxygen exposure.miRNA-21-5p may play an important role in the formation of BPD through down expression. |
PDF Full Text Request