Bronchopulmonary dysplasia(BPD)is the main cause of chronic respiratory diseases in preterm infants.The research on the prophylaxis and treatment of BPD has been a concern of neonatologists because of its high incidence and poor prognosis in preterm infants.Glucocorticoid is a major therapy in the treatment of BPD because the pathological changes of BPD are characterized by persistent lung inflammation.Until now, a large number of clinical studies including different types and administration methods of glucocorticoids have been conducted.Compared with other types of glucocorticoids, low-dose and short-course dexamethasone has its unique advantages in the treatment of BPD.This article reviews the role of inflammation in the pathogenesis of BPD and the research progress of glucocorticoids in the prophylaxis and treatment of BPD.

Objective To explore the role of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in hyperoxia-induced lung injury in preterm rats. Methods At the 2 nd postnatal day Sprague-Dawley preterm rats were randomly assigned to air group and hyperoxia group (exposed to about 85% of O 2). At 3,7,14 and 21 days after exposure, six rats of each group were used to assess lung histologic changes and expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 in lungs by immunohistochemistry. At 3,7 and 14 days after exposure, gelatinase activity in bronchoalveolar lavage fluid (BALF) of another six rats in each group by gelatin zymography was examed. Results Except 3 d after exposure, hyperoxia group showed lung injury characterized by subacute alveolitis and inhibition of lung development. Expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 in hyperoxia group was stronger than that in air group at every time (P

This study examined the effects of retinoic acid (RA), PD98059, SP600125 and SB203580 on the hyperoxia-induced expression and regulation of matrix metalloproteinase-2 (MMP-2) and metalloproteinase-2 (TIMP-2) in premature rat lung fibroblasts (LFs). LFs were exposed to hyperoxia or room air for 12 h in the presence of RA and the kinase inhibitors PD98059 (ERK1/2), SP600125 (JNK1/2) and SB203580 (p38) respectively. The expression levels of MMP-2 and TIMP-2 mRNA were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). MMP-2 activity was measured by zymography. The amount of p-ERK1/2, REK1/2, p-JNK1/2, JNK1/2, p-p38 and p38 was determined by Western blotting. The results showed that: (1) PD98059, SP600125 and SB203580 significantly inhibited p-ERK1/2, p-JNK1/2 and p-p38 respectively in LFs; (2) The expression of MMP-2 mRNA in LFs exposed to hyperoxia was decreased after treatment with RA, SP600125 and SB203580 respectively (P<0.01 or 0.05), but did not change after treatment with PD98059 (P>0.05). Meanwhile, RA, PD98059, SP600125 and SB203580 had no effect on the expression of TIMP-2 mRNA in LFs exposed to room air or hyperoxia (P>0.05); (3) The expression of pro- and active MMP-2 experienced no change after treatment with RA or SP600125 in LFs exposed to room air (P>0.05), but decreased remarkably after hyperoxia (P<0.01 or 0.05). SB203580 inhibited the expression of pro- and active MMP-2 either in room air or under hyperoxia (P<0.01). PD98059 exerted no effect on the expression of pro- and active MMP-2 (P<0.05). It was suggested that RA had a protective effect on hyperoxia-induced lung injury by down-regulating the expression of MMP-2 through decreasing the JNK and p38 activation in hyperoxia.

Objective To determine whether the inhibition of paxillin tyrosine residues 31 and tyrosine residues 118 (Pxn Y31 and Pxn Y118) phosphorylation via inhibition of c-Abl kinase will effectively block its downstream effector molecules vessel endothelium-cadherin (VE-cad), and whether Rho/Rho kinase activation which will induce the vascular barrier dysfunction. Methods Ninety healthy male Sprague-Dawley (SD) rats were randomly divided into nine groups (each n =10). Only tracheotomy was undergone in the sham group. Groups of protective ventilation were set at a volume tidal (VT) of 6 mL/kg, a positive end-expiratory pressure (PEEP) of 5 cmH2O (1 cmH2O =0.098 kPa) for 1 hour or 2 hours (namely group PVT 1 h and group PVT 2 h), respectively. Groups of high VT were put on mechanical ventilation (MV) at high VT 30 mL/kg, PEEP 0 for 1 hour or 2 hours (namely group HVT 1 h and group HVT 2 h), respectively. Groups UO126 and AG957 pretreatment were set on MV at HVT for 1 hour or 2 hour respectively, but they were given p42/44 mitogen-activated protein kinase (p42/44MAPK) inhibitor UO1261 mg/kg by intraperitoneal injection or c-Abl kinase inhibitor AG95710 mL/kg by intragastric injection 1 hour before HVT ventilation. All the animals were sacrificed after experiments and specimens of lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. Pulmonary vascular permeability was measured by Evans blue (EB). The levels of tumor necrosis factor-α(TNF-α) in BALF were measured by enzyme linked immunosorbent assay (ELISA). Then the change of lung tissue pathology was observed with light microscope, diffuse alveolar damage system (DAD) score and lung wet/dry ratio (W/D) were estimated. The myeloperoxidase (MPO) activity was measured by colorimetric analysis, phosphorylations of c-Abl Y245, Pxn Y31, Pxn Y118, VE-cad Y658, p42/44MAPK Y202/Y204, myosin light chain (MLC) and myosin-associated phosphatasetype Y696 (MYPT Y696) were determined by Western Blot. Results ① There were no obvious pathological changes in the lung tissue in the sham group and PVT 1 h or 2 h group, and also there were no significant differences in all the parameters between above groups. However, the injury in lung tissue was severe in the HVT groups. In addition, DAD score, lung W/D ratio, EB content, the activity of MPO, and TNF-α in BALF in HVT groups were significantly higher than those in sham group and PVT groups. After pretreatment with AG957 or UO126, all the parameters were significantly decreased as compared with those of groups HVT. ② The levels of phosphorylation of the proteins in lung tissue in HVT groups were increased as compared with those of group sham and groups PVT, especially at 2 hours of MV. However, compared with groups HVT, the level of p-VE-cad Y658 in lung tissue decreased significantly in group AG957 and group UO126 at 2 hours after HVT. However, the levels of all phosphorylated proteins at 2 hours were significantly lowered in the AG957 group compared with those of the HVT group [p-c-Abl Y245 (gray value): 0.29±0.04 vs. 0.42±0.04, p-Pxn Y31 (gray value): 0.51±0.03 vs. 0.70±0.05, p-Pxn Y118 (gray value):0.65±0.04 vs. 0.91±0.04, p-VE-cad Y658 (gray value): 0.77±0.07 vs. 1.32±0.07, p-p42/44MAPK Y202/Y204 (gray value): 0.38±0.06 vs. 0.61±0.03, p-MLC (gray value): 0.37±0.04 vs. 0.77±0.05, p-MYPT Y696 (gray value):0.54±0.05 vs. 0.87±0.06, all P < 0.05]. After pretreatment with UO126, the phosphorylation level of VE-cad in lung tissue at 2 hours was significantly lower than that of HVT group (gray value: 0.74±0.04 vs. 1.32±0.07), and the phosphorylation levels of p42/44MAPK and its downstream effector molecules MLC and MYPT Y696 were also significantly decreased [p-p42/44MAPK Y202/Y204 (gray value): 0.38±0.07 vs. 0.61±0.03, p-MLC (gray value):0.37±0.04 vs. 0.77±0.05, p-MYPT Y696 (gray value): 0.55±0.05 vs. 0.87±0.06, all P < 0.05]. Conclusions Pxn Y31 and Pxn Y118 phosphorylation could be blocked by inhibition of c-Abl kinase, which could strengthen VE-cad at attachment junction and might block formation of Pxn-guanine nucleotide-exchange factor H1 (GEF-H1)-p44/42MAPK signalosome which induce activation local Rho signaling, lead to activation of MLC phosphorylation, actomyosin contraction, and increase endothelial permeability.

ObjectiveTo determine whether the inhibition of caveolin-1 tyrosine residues 14 (Cav-1-Y14) phosphorylation with protein tyrosine kinase inhibitors (PP2) will upregulate heme oxygenase-1 (HO-1) activity to protect against ventilation induced lung injury in vivo of an animal model.Methods Fifty-four male Sprague-Dawley (SD) rats were randomly divided into nine groups (eachn = 6). Group A served as normal control group, in which rats did not receive ventilation but tracheotomy. Groups B1 and B2 received lung protective ventilation respectively for 1 hour or 2 hours. Groups C1 and C2 received high tidal volume (40 mL/kg) ventilation for 1 hour or 2 hours, respectively. The group D1 or D2 also received high tidal volume ventilation for 1 hour or 2 hour respectively, but they were given PP2 1 hour before high tidal volume ventilation. The groups E1 and E2 also received high tidal volume ventilation respectively for 1 hour or 2 hours, but tyrosine kinase inhibitor PP2 and HO-1 inhibitor zinc protoporphyrinⅨ(ZnPPⅨ) were given to animals 18 hours before high tidal volume ventilation. All the animals were sacrificed after ventilation, and the specimens of lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. Then the changes in pathology of lung tissue was observed, and diffuse alveolar damage scores (DAD) were calculated, myeloperoxidase (MPO) activity was measured by colorimetric analysis, lung wet/dry ratio (W/D) was estimated. The expressions of phosphorylated caveolin-1 (P-Cav-1-Y14), caveolin-1 (Cav-1) and HO-1 were determined by Western Blot. The expressions of high mobility group B1 (HMGB1) and advanced glycation end product receptor (RAGE) in lung tissues were assayed with immunohistochemistry staining. The levels of tumor necrosis factor-α(TNF-α) in BALF were measured by enzyme linked immunosorbent assay (ELISA).Results There was no significant difference in all the parameters between group A and groups B. Compared with group B1, DAD score, W/D ratio, the activity of MPO and the concentration of TNF-α in BALF in group C1 were significantly increased [DAD score:7.97±0.59 vs. 0.55±0.13, W/D ratio: 5.70±1.61 vs. 5.04±0.63, MPO (U/g): 1.82±0.14 vs. 0.77±0.26, TNF-α(ng/L): 370.10±29.61 vs. 54.38±8.18, allP< 0.05], and the injury in ventilation 2 hours group was more serious than that in ventilation 1 hour group. Compared with groups C, all the parameters in groups D were significantly decreased. The parameters in groups E were significantly higher than those in groups A, B, and D, but no significant difference was found as compared with groups C. Compared with groups B, the protein expressions of Cav-1 and P-Cav-1-Y14 (gray value) in groups C were significantly increased (1 hour: 1.49±0.02 vs. 1.26±0.13, 1.34±0.02 vs. 0.87±0.04;2 hours: 1.58±0.02 vs. 1.27±0.27, 1.31±0.01 vs. 0.95±0.02, allP< 0.05), and the expression of HO-1 protein (gray value) was significantly decreased (1 hour: 0.59±0.02 vs. 1.10±0.01, 2 hours: 0.49±0.01 vs. 1.20±0.02, both P< 0.05). No significant difference in Cav-1 protein expression between groups D as well as groups E and groups C. The protein expression of P-Cav-1-Y14 in groups D and E was significantly lower than that in groups C. The protein expression of HO-1 in groups D was significantly higher than that in groups C, but the phenomenon was not found in groups E as compared with groups C. Compared with group A, the positive expression of HMGB1 and RAGE in lung tissue in groups C and E was significantly increased, but no significant difference was found between groups B as well as groups D and group A.Conclusion Cav-1-Y14 phosphorylation is the key factor for ventilator induced lung injury, which can not only lead to a decrease in vascular barrier function, but also inhibit the activity of HO-1 enzyme, thus further aggravates inflammatory injury of the lung as induced by mechanical ventilation.

Objective To investigate the efficacy and safety of aminophylline,caffeine citrate and aminophylline combined with naloxone in prevention of apnea of prematurity(AOP).Methods Ninety-four infants with a birth weight ＜ 1 500 g and gestational age ＜ 34 weeks admitted to Department of Pediatrics,Tongji Hospital Affiliated to Tongji Medical College,Huazhong University of Science and Technology between Jan.2010 and Jan.2012 were randomly divided into 3 groups.(1) Aminophylline group (n =30):30 infants received a loading dose of 4-5 mg/kg of aminophylline and then maintained by a dose of 2 mg/kg,with intravenous drip q12 h.(2) Caffeine citrate group(n =32):a loading dose of 20 mg/kg of caffeine citrate was followed by a daily maintained dose of 5 mg/kg,with intravenous drip per day.(3) Aminophylline combined naloxone group (observation group,n =32):32 infants were treated with Aminophylline combined with naloxone.After 6 hours of the first dose of aminophylline,a dose of 0.1 mg/kg naloxone was injected,q12 h.Then the two drugs were used alternately.The mortality and incidence of AOP,bronchopulmonary dysplasia(BPD),retinopathy of prematurity (ROP) and brain injury were evaluated,and drug-related side effects were recorded.Results 1.There was no significant difference in gender,gestational age,birth weight,maternal antenatal glucocorticoid application,pregnancy (including multiple pregnancy) and delivery,5 min Apgar score,oxygen therapy,and the application of positive airway pressure as well as pulmonary surfactant among the 3 groups(all P ＞0.05).2.Compared with aminophylline group,the incidence of apnea of caffeine group and observation group were significantly lower (F =6.704,P ＜ 0.05),but there was no significant difference between caffeine group and observation group (P ＞0.05).3.There was no statistically significant difference in mortality,duration of oxygen therapy,the incidence of ROP,brain injury and hearing loss,postmenstrual age,body weight at discharge,the duration and cost of hospitalization among the 3 groups(all P ＞0.05).4.The BPD incidence in caffeine group[9.4％ (3/32 cases)] and observation group [12.5％ (4/32 cases)] were lower than that in Aminophylline group [20.0％ (6/30 cases)],but there was no statistical significance among the 3 groups(P ＞ 0.05).5.No drug-related side effects were recorded in the 3 groups.Conclusions It is safe and effective to use aminophylline combined with naloxone in prevention of AOP,and its efficiency is similar to caffeine citrate.

Objective To investigate the diagnosis,treatment and prognosis of neonates with severe acute respiratory distress syndrome (ARDS) according to Berlin definition.Methods A retrospective study was carried to analyze the clinical features about diagnosis,treatment,chest X-ray findings,mortality,complications and ventilator parameters in 86 neonates with severe ARDS admitted in the NICU from January 2005 to December 2013.Results (1)Among the 86 cases,55 were cured,and 31 died with 36.0％ mortality.(2) Chest X-ray showed there was decreased lucency of bilateral lungs with ground-glass appearance,lung texture with thick chaos or dot flakes or patchy shadows in 36 neonates; diffuse infiltrates and extensive confluent consolidation shadows in bilateral lungs along with peripheral air brornchograms in 26 cases; heart shadow and diaphragmatic surface disappeared like a white lung change in 24 cases.(3) Persistent pulmonary hypertension of newborn as a complication occurred in 68 cases with 79.1％ incidence.(4) Eighty-six cases were categorized into survival group and death group.The results showed compared with the survival group,the neonates in death group required higher FiO2,and PaO2,and lower PaO2/FiO2 before mechanical ventilation (P ＜ 0.01),but needed higher initial PIP of mechanical ventilation (P ＜ 0.01).Conclusions Neonatal ARDS is still a kind of critical condition with high mortality and lack of evidence-based diagnostic criteria so far.The therapeutic strategy for neonatal ARDS should be a comprehensive measures in addition to appropriate respiratory support.

Objective To investigate whether the inhibition of caveolin-1 (Cav-1) phosphorylation will regulate effectively nuclear factor-erythroid 2-related factor (Nrf2) signal pathway and downstream effector molecules and protest against ventilation induced lung injury (VILI) in an animal model in vivo. Methods Ninety male Sprague-Dawley (SD) rats were randomly divided into nine groups (each n = 10): sham group in which rats did not receive ventilation but received tracheotomy; lung protective ventilation (PV) for 1 hour or 2 hours group; mechanical ventilation (MV) at high volume tidal (VT, 40 mL/kg) for 1 hour or 2 hours group; protein tyrosine kinase inhibitor PP2 or rosiglitazone (Rsg) pretreatment + high VT ventilation for 1 hour or 2 hours groups. The two pretreatment groups were given intraperitoneal injection PP2 15 mg/kg or intragastric administration of Rsg 5 mg/kg 1 hour before ventilation respectively. The rats were sacrificed after model reproduction, and bronchoalveolar lavage fluid (BALF) was collected. Pulmonary vascular permeability was measured by Evans blue (EB). The levels of tumor necrosis factor-α (TNF-α), activator protein-1 (AP-1), nuclear factor-κB (NF-κB), and interleukin-8 (IL-8) in BALF were determined by enzyme linked immunosorbent assay (ELISA). Then the lung tissues were collected, the lung wet/dry ratio (W/D) was calculated, the changes in pathology was observed with light microscope, and myeloperoxidase (MPO) activity was determined by colorimetric analysis. Nrf2 mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of Cav-1 tyrosine residues 14 phosphorylation (pCav-1-Y14), Cav-1, peroxisome proliferators-activated receptor γ (PPARγ) and claudin-5 as well as Nrf2 in cytoplasm and nucleus were determined by Western Blot. The positive expressions of PPARγ and claudin-5 in lung tissues were assayed with immunohistochemistry staining. Results There were no obvious pathological changes in the lung tissue in sham group and PV groups, and there were no significant differences in all the parameters between the two groups either. However, the injury in lung tissue was severe in the high VT groups in which W/D ratio, EB contents, MPO activity, and TNF-α, AP-1, IL-8, NF-κB levels in BALF as well as the protein expressions of Cav-1 and pCav-1-Y14 were significantly higher than those of sham group and PV groups, and the protein expressions of PPARγ and claudin-5 were significant lower than those of sham group and PV groups with a dose-dependent manner; but Nrf2 expressions in cytoplasm and nucleus did not show a statistical increase. After pretreatment of PP2 or Rsg, W/D ratio, MPO activity, EB contents, TNF-α, AP-1, IL-8, and NF-κB in BALF were significantly decreased as compared with those of high VT group, and RT-PCR showed significant up-regulation of Nrf2 mRNA in lung tissues too. Moreover, there was a statistically significant increase in expressed Nrf2 proteins in nucleus in PP2 or Rsg groups as compared with those of high VT groups [Nrf2 in nucleus (gray value): 0.61±0.06, 0.56±0.06 vs. 0.31±0.02 at 1 hour, 0.38±0.06, 0.43±0.07 vs. 0.22±0.03 at 2 hours; all P < 0.05], but no significant difference was found in the expression of Nrf2 protein in the cytoplasm among all groups. The protein expressions of pCav-1-Y14 in PP2 pretreatment groups were significantly lower than those of high VT groups (gray value: 0.89±0.04 vs. 1.48±0.02 at 1 hour, 0.86±0.02 vs. 1.31±0.01 at 2 hours; both P < 0.05); but expressed PPARγ proteins and expressed claudin-5 proteins in PP2 or Rsg pretreatment groups were significantly higher than those of high VT groups [PPARγ (gray value): 0.34±0.07, 0.42±0.13 vs. 0.17±0.07 at 1 hour, 0.38±0.09, 0.33±0.07 vs. 0.16±0.03 at 2 hours; claudin-5 (gray value): 0.33±0.05, 0.38±0.07 vs. 0.14±0.03 at 1 hour; 0.30±0.06, 0.31±0.04 vs. 0.17±0.04 at 2 hours; all P < 0.05]. Conclusions The inhibition of Cav-1-Y14 phosphorylation can increase the expression of Nrf2 in the nucleus, then result in an increase in the protein expressions of PPARγ and claudin-5 of its effector molecules. This effect can reduce the inflammation and capillary permeability of lung tissue in the model of VILI.

Objective To investigate the neuroprotective effects and mechanisms of 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/ IMP cyclohydrolase(AICAR) supplement (AMPK activator) in different stages of neonatal rats sufferring from hypoxia-ischemia encephalopathy ( HIE). Methods Neonatal rat hypoxia-ischemia brain injury model was employed in this study. A total of 160 neonatal rats were distributed into five groups: sham, model control,AICAR30 min, AICAR24 h and AICAR72 h. The neuroprotective effects of AICAR supplement (30 min, 24 h, 72 h post operation) were compared by cresyl violet staining; Expressions of P-AMPK,AMPK in the brain tissue were measured by Western blotting.Foot-faults method was used to evaluate the long-term prognosis of the rats. Results Compared with the sham group, the survival of rats brain in model control group was significantly decreased [(100.0± 0.1)% and (45.3± 6.3)%, P< 0.05]. AICAR had neuroprotective effects when treated at 30 min and 24 h post operation,while the protective effects disappeared when treated later (72 h post operation) (P>0.05). Compared with the sham group, the expression of P-AMPK significantly increased about three times, while ATP level decreased close to the same. Conclusion Early AICAR treatment can protect hypoxia-ischemia brain injury by increasing AMPK-ATP level.

Objective To determine the dynamic changes in adenosine monophosphate-activated protein kinase (AMPK) in neurons of neonatal rats suffering from hypoxic ischemic brain injury.Methods Twenty-four-hour old and seven-day old neonatal rats were used in this study.A classic primary cortical neuron oxygen glucose deprivation (OGD) model and neonatal rat hypoxic ischemic encephalopathy (HIE) model were employed.Lactic dehydrogenase (LDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were used to evaluate neuron viability and damage.The expression of phosphorylated adenosine monophosphate-activated protein kinase (P-AMPK),phosphorylated activated protein kinase (P-Akt) and Cleaved Caspase-3 in neurons and brain tissue was measured by Western blot at different time points after OGD or HIE.The Student-t test was used for statistical analysis.Results (1) Compared with the control group,LDH levels at 2,4,8 and 24 h after OGD were higher (all P＜0.05) and optical absorption levels of MTT were lower (all P＜0.05).(2) Levels of P-AMPK in the OGD group were higher than those in the control group,and showed a time-dependent increase at 30 min and 2,4,8 and 24 h (all P＜0.05).The expression levels of P-AMPK in the HIE group were higher than those in the control group (0.345 ± 0.038,0.387 ± 0.112 and 0.618 ± 0.075 at 1,3 and 7 days after HIE,and 0.132±0.032 in the control group,all P＜0.05).(3) The levels of P-Akt increased above the control levels at 30 min (0.991 ±0.134 vs 0.304±0.050),reached a maximum level at 2 h (1.183± 0.107),and then gradually declined,whereas the levels of Cleaved Caspase-3 started to increase at 30 min,and remained elevated at 24 h (all P＜0.05).Conclusion Following hypoxic ischemic brain damage,the expression of P-AMPK is significantly increased in both in vivo and in vitro studies in a time-dependent manner.