Objective To investigate the changes and potential roles of the expression of apoptosis signal-regulating kinase 1(ASK1),thioredoxin(Trx)and thioredoxin reductase(TrxR)in the pathogenesis of lung injury of premature newborn rats exposed to hyperoxia. Methods In the first day after delivery,preterm SD rats were randomly divided into air group and hyperoxia group with 64 rats in each.The rats were respectively sacrificed at 1,4,7,10 and 14 days after air or hyperoxia exposure.Sections of 1ungs were stained with HE to observe the histologic changes.Trx and TrxR mRNA were detected by reverse transcription-polymerase chain reaction(RT-PCR).Immunohistochemistry was used to detect the expression and distribution of ASK1.Western blot was used to detect the expression of ASK1 protein. Results Rats in hyperoxia group showed typical lung injury,which was characterized by alveolitis and delayed of lung development.Immunohistochemistry detected that ASK1 expressed generally in the cytoplasm of both alveolar epithelial cells and vascular endothelial cells:ASK1 protein expression in hyperoxia group at 1th and 4th day were 0.4382±0.0227 and 0.5270±0.0432,higher than in the air group(0.3458±0.0263 and 0.3760±0.0058)(P<0.01),and it was until 7th day that the expression became weaker(0.4343±0.0254),but still higher compared with the air group(0.3473±0.0220)(P<0.01).Compared with the air group,Trx and TrxR mRNA of the hyperoxia group increased significantly and peaked at lOth day(0.6860±0.0811)and 7th day(2.0351±0.1600),respectively(P<0.05).ASK1 protein expressions resulting

Objective To explore the effects of expression of thioredoxin-2(Trx-2) suppressed by small interference RNA(SiRNA) in A549 cells exposed to hyperoxia on expression of nicotinamide adenine dinucleotide(NADH) dehydrogenase subunit 1(ND1)and cytochrome C oxidase Ⅰ(COX Ⅰ). Methods A549 cells were gained by serial subcultivation in vitro and transfered with synthetic Trx-2 sequence-specific SiRNA and then were randomly divided into air group without interference,hyperoxia group without interference,air group after interference,and hyperoxia group after interference.After exposure to oxygen or room air for 12,24 and 48 h,expressions of Trx-2,ND1 and COX Ⅰ mRNA of these cells were detected by reverse transcription-polymerase chain reaction (RT-PCR),and Trx-2 protein was detected by Western blot. Results (1)Sequence-specific SiRNAtargeting Trx-2 could significantly down-regulate its expression in A549 cells.(2)Trx-2 mRNA levds inhyperoxia group without interference at 24 h was higher than those in air group without interference(0.7799±0.1249 VS 0.4424±Ⅰ.1140,P<0.05).Th-2 mRNA levels in hyperoxia group after ireedcrence at 24 hand 48 h were 0.2774±0.0174 and 0.2587±0.0069,lower than those in air group after interference andhyperoxia group without interference (P<0.05).(3)ND1 mRNA levels in hyperoxia group without interference at 24 h was 0.6609±0.0368,lower than those in air group without interference(0.8898±0.1049)(P<0.05).ND1 mRNA levels in hyperoxia group after interference at 12 h was 0.8848±0.0135,higher than those in air group after imederence(P<0.05).ND1 mRNA levels in hypemxia group afterinterference at 48 h was 0.3808±0.0937,lower than those in air group after imerference and hyperoxiagroup without interference(P<0.05).(4)COXI mRNA levels in hypemxia group without inteference at 12,24 and 48 h were 1.7313±0.4331,2.1929±0.6722 and 2.0754±0.2584,higher than those in air group witheUt interference,respectively (P<0.05). Conclusions ND1 and COXⅠ participate in thedevelopment of hyperoxia indUCed lung.injury,and Trx-2 is likely to have protective effect on mitochondria ofA549 cells in hyperoxia lung injury.

This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 (Trx1) and thioredoxin reductase-1 (TrxR1) in alveolar type II epithelial cells (AECII) of premature rats. Pregnant Sprague-Dawley rats were sacrificed on day 19 of gestation. AECII were isolated and purified from the lungs of premature rats. When cultured to 80% confluence, in vitro cells were randomly divided into air group and hyperoxia group. Cells in the hyperoxia group were continuously exposed to 95% O(2)/5% CO(2) and those in the air group to 95% air/5% CO(2). After 12, 24 and 48 h, cells in the two groups were harvested to detect their reactive oxygen species (ROS), apoptosis, TrxR1 activity and the expressions of Trx1 and TrxR1 by corresponding protocols, respectively. The results showed that AEC II exposed to hyperoxia generated excessive ROS and the apoptosis percentage in the hyperoxia group was increased significantly at each time points as compared with that in the air group (P<0.001). Moreover, TrxR1 activity was found to be markedly depressed in the hyperoxia group in comparison to that in the air group (P<0.001). RT-PCR showed the expressions of both Trx1 and TrxR1 mRNA were significantly increased in AECII exposed to hyperoxia for 12 and 24 h (P<0.01), respectively. At 48 h, the level of Trx1 mRNA as well as that of TrxR1 mRNA in the hyperoxia group was reduced and showed no significant difference from that in the air group (P>0.05). Western blotting showed the changes of Trx1 protein expressions in the hyperoxia group paralleled those of Trx1 mRNA expressions revealed by RT-PCR. It was concluded that hyperoxia can up-regulate the protective Trx1/TrxR1 expressed by AECII in a certain period, however, also cause dysfunction of the cytoplasmic thioredoxin system by decreasing TrxR1 activity, which may contribute to the progression of oxidative stress and cell apoptosis and finally result in lung injury.

This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 (Trx1)and thioredoxin reductase-1 (TrxR1) in alveolar type Ⅱ epithelial cells (AECⅡ) of premature rats.Pregnant Sprague-Dawley rats were sacrificed on day 19 of gestation.AEC Ⅱ were isolated and purified from the lungs of premature rats.When cultured to 80％ confluence,in vitro cells were randomly divided into air group and hyperoxia group.Cells in the hyperoxia group were continuously exposed to 95％ O2/5％ CO2 and those in the air group to 95％ air/5％ CO2.After 12,24 and 48 h,cells in the two groups were harvested to detect their reactive oxygen species (ROS),apoptosis,TrxR1 activity and the expressions of Trx1 and TrxR1 by corresponding protocols,respectively.The results showed that AEC Ⅱ exposed to hyperoxia generated excessive ROS and the apoptosis percentage in the hyperoxia group was increased significantly at each time points as compared with that in the air group (P＜0.001).Moreover,TrxR1 activity was found to be markedly depressed in the hyperoxia group in comparison to that in the air group (P＜0.001).RT-PCR showed the expressions of both Trx1 and TrxR1 mRNA were significantly increased in AEC Ⅱ exposed to hyperoxia for 12 and 24 h (P＜0.01),respectively.At 48 h,the level of Trx1 mRNA as well as that of TrxR1 mRNA in the hyperoxia group was reduced and showed no significant difference from that in the air group (P＞0.05).Western blotting showed the changes of Trx 1 protein expressions in the hyperoxia group paralleled those of Trx1 mRNA expressions revealed by RT-PCR.It was concluded that hyperoxia can up-regulate the protective Trx1/TrxR1 expressed by AEC Ⅱ in a certain period,however,also cause dysfunction of the cytoplasmic thioredoxin system by decreasing TrxR1 activity,which may contribute to the progression of oxidative stress and cell apoptosis and finally result in lung injury.

Objective:Lung ultrasound (LUS) has been used in the diagnosis of neonatal respiratory distress syndrome(RDS) successfully, but there have been no multicenter prospective studies to verify its reliability or determine how to grade RDS with LUS findings.This study aimed to discuss the necessity and feasibility of using LUS findings to determine RDS grades through a multicenter prospective study.Methods:Every researcher participated in the National Neonatal Lung Ultrasound Training Course and receiving 3-6 months of lung ultrasound system training at the National Neonatal Lung Ultrasound Training Center.Patients between June 2018 and May 2020 who met the RDS ultrasound diagnostic criteria and had full available clinical data were included in this study.The LUS examination was completed immediately after the patients were admitted to the hospital.Some of them also underwent chest X-ray examination.Arterial blood gas analysis was completed immediately before or after the LUS ultrasound examination.RDS grading was performed according to the LUS findings and whether the patient had serious complications.Results:A total of 275 qualifying cases were included in this study, which included 220 premature infants and 55 full-term infants, and the primary RDS occurred in 117 cases (42.5%), and secondary RDS occurred in 158 cases (57.5%). LUS manifestations of RDS patients can be divided into three categories: (1)A ground-glass opacity sign: which could be found among 50 infants when they were admitted to the hospital (that was, at their first LUS examination). Twenty-eight of these infants were considered to have wet lungs and were not sent for special management on admission, but LUS showed typical snowflake-like lung consolidation within 0.5 to 4 hours.Twenty-two of them were given mechanical ventilation with exogenous pulmonary surfactant; Eighteen cases were controlled within 6-12 hours, but the lung lesions became more severe in the other 4 infants (due to severe intrauterine infection). (2)Snowflake-like lung consolidations: the first LUS on admission showed typical snowflake-like lung consolidation involving areas ranging from 1-2 intercostal spaces to 12 lung divisions in 204 cases.Thirty-eight infants among them the lung consolidation only had involvement of 1-2 intercostal spaces at the time of admission; Fifteen of them received invasive respiratory support and recovered within 4-12 hours.Twelve patients received noninvasive respiratory support; Seven of them recovered, while five cases developed severe lung illness.The remaining 11 patients who were not given any form of ventilator support developed severe conditions within 1-4 hours.Thirty of them showed snowflake signs involving 12 lung regions at admission.The remaining 136 patients had lung consolidation degree between the two degree above condition.(3)Snowflake-like sign with complications: Twenty-one patients had severe complications such as pneumothorax, pulmonary hemorrhage or/and persistent pulmonary hypertension of the newborn or large area atelectasis, etc, although snowflake lung consolidation did not involve all lung regions.Conclusion:(1) LUS is reliable and accurate for diagnosing RDS.RDS has the same characteristics on ultrasound for both preterm and full-term infants, both primary and secondary RDS.(2) To facilitate the management of RDS, it is necessary to classify RDS according to the ultrasound findings and the presence of severe complications.(3) Based on the results of this study, it is recommended that RDS can be divided into mild, moderate and severe degrees.The exact standards for grading are as follows: Mild RDS: the early stage of RDS, in which lung consolidation shows as a ground-glass opacity sign on ultrasound; Moderate RDS: lung consolidation shows a snowflake sign on ultrasound, not all of the lung fields are involved; Severe RDS meets one or more of the following criteria: lung consolidation shows as a snowflake sign on ultrasound and all lung regions are involved, or regardless of its degree and extent, lung consolidation has caused serious complications, such as pulmonary hemorrhage, pneumothorax, persistent pulmonary hypertension of the newborn, or/and a large area of pulmonary atelectasis.

Objective: To investigate the effect of hypertensive disorder complicating pregnancy (HDCP) on the mortality and early complications of premature infants. Methods: The general clinical data of preterm infants with gestational age 24-36^{+ 6} weeks were collected from the cooperative units in the task group from January 1, 2013 to December 31, 2014.According to the severity of HDCP, the infants were divided into 4 groups: HDCP group, preeclampsia group, eclampsia group and non HDCP group, the mortality and major complications of preterm infants were compared, and the influencing factors were analyzed. Results: The mortality rate of preterm in the HDCP group was significantly higher than that of non HDCP group, and there was statistical significance (χ²=9.970, P=0.019). Eclampsia had a highest fatality rate (4.8%) in the early stage, compared with non HDCP group (2.2%), and the difference was statistically significant.Comparison of HDCP group (1.8%) and eclampsia group (3.2%) suggested that there was no statistically significant difference.The incidence of respiratory distress syndrome (RDS) in preterm in HDCP group was significantly higher than that of non HDCP group, and there was statistical significance (χ²=13.241, P=0.004). Eclampsia group showed the highest incidence (35.4%), compared with non HDCP group (16.2%), the difference was statistically significant, but compared with HDCP group (19.9%), preeclampsia group (17.1%), there was no significant diffe-rence.The incidence of bronchopulmonary dysplasia (BPD) in preterm in HDCP group was significantly higher than that of non HDCP group (χ²=9.592, P=0.022), the highest incidence showed up in eclampsia group (9.7%), compared with non HDCP group (2.0%) and HDCP group (1.7%), the difference was statistically significant.But there was no statistically significant difference, compared with preeclampsia group.As the degree of HDCP aggravated, the incidence of BPD gradually rose.There was no significant impact on necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH) and sepsis of HDCP (χ²=7.054, 7.214, 0.358, 3.852; P=0.070, 0.065, 0.949, 0.278). Considering the overall outcome of the child, that was, whether the child died or survived, he had at least one complication, and HDCP had an effect on it (χ²=15.697, P=0.001), so the incidence increased while the degree of HDCP rose gradually.After adjusting gestational age, birth weight, sex, way of delivery, placental abruption and front placenta, prenatal hormonal, gestational diabetes, neonatal asphyxia and other factors, the results displayed that HDCP was the factor leading to the death of premature baby (OR=2.159, 95%CI: 1.093-4.266), and comparison between preeclampsia and eclampsia showed no statistical difference (P=0.714, 0.389); HDCP had no significant influence on RDS, BDP, ICH, NEC, ROP and sepsis. Conclusions HDCP leads to increased risk of premature death, but also leads to the increased incidence of RDS and BPD, but it had no obvious effect on NEC, ROP, IVH, sepsis and other complications.