ABSTRACT
Objective:To observe the expression changes of nuclear factor erythroid 2 related factor 2 (Nrf2) and glutathione peroxidase (GPX4) in human pulmonary microvascular endothelial cells (HPMEC) under different experimental conditions, and to explore the role of Nrf2 in inhibiting ferroptosis in the process of alleviating hyperoxic lung injury(HLI).Methods:Hyperoxic model was established by hyperoxia exposure.HPMEC were treated with blank control (control group), oxygen exposure at the concentration of 950 mL/L (hyperoxia group), oxygen exposure at the concentration of 950 mL/L+ 10 μmol/L Ferrostatin (ferroptosis inhibitor group) and oxygen exposure at the concentration of 950 mL/L + 10 μmol/L ML385 (Nrf2 inhibitor group). Cell viability at 24 h and 48 h was tested by the Cell Counting Kit-8 assay, and reactive oxygen species (ROS) levels were detected by a commercial ROS kit.The mRNA and protein levels of Nrf2 and GPX4 were detected by real-time quantitative polymerase chain reaction and Western blot, respectively.Differences were analyzed using the Student′s t-test for a two-group comparison or one-way ANOVA test among groups. Results:(1)Compared with the control group, significantly decreased viability and increased ROS levels were detected in hyperoxia group.Meanwhile, the mRNA (24 h: 0.750±0.010 vs.1.010±0.160, 48 h: 0.690±0.050 vs.1.000±0.070) and protein levels of GPX4 (24 h: 0.160±0.010 vs.0.290±0.010, 48 h: 0.190±0.010 vs.0.250±0.010) at 24 h and 48 h were significantly downregulated, while the mRNA (24 h: 1.740±0.050 vs.1.000±0.050, 48 h: 2.130±0.020 vs.1.000±0.030) and protein levels of Nrf2 (24 h: 0.840±0.010 vs.0.480±0.010, 48 h: 0.840±0.010 vs.0.550±0.030) at 24 h and 48 h were significantly upregulated in hyperoxia group than those of control group (all P<0.05). (2)Compared with the hyperoxia group, significantly increased viability and decreased ROS levels were detected in ferroptosis inhibitor group.Meanwhile, the mRNA (24 h: 1.520±0.110, 48 h: 1.880±0.050) and protein levels of GPX4 (24 h: 0.290±0.010, 48 h: 0.250±0.004) at 24 h and 48 h were significantly upregulated, while the mRNA (24 h: 0.780±0.040, 48 h: 0.760±0.030) and protein levels of Nrf2 (24 h: 0.480±0.010, 48 h: 0.540±0.020) at 24 h and 48 h were significantly downregulated in ferroptosis inhibitor group than those of hyperoxia group (all P<0.05). (3)Compared with the hyperoxia group, significantly decreased viability and increased ROS levels were detected in Nrf2 inhibitor group.Meanwhile, the mRNA (24 h: 0.600±0.030, 48 h: 0.590±0.003) and protein levels of GPX4 (24 h: 0.150±0.001, 48 h: 0.180±0.001) at 24 h and 48 h were significantly downregulated, while the mRNA level of Nrf2 was significantly upregulated at 24 h (3.360±0.130), but downregulated at 48 h (1.430±0.130) (all P<0.05). No significant difference was detected in the protein level of Nrf2 at 24 h and 48 h between hyperoxia group and Nrf2 inhibitor group ( P>0.05). Conclusions:Ferroptosis is involved in the development of HLI, and Nrf2 is able to alleviate hyperoxic lung injury by inhibiting ferroptosis.Therefore, inhibition of ferroptosis by Nrf2 may provide a new therapeutic target for HLI.
ABSTRACT
Objective: To explore the protective effect of glutamine (GLN) on the hyperoxia lung injury in the neonatal rats, and to elucidate its mechanism. Methods: A total of 90 male and female Wistar rats were selected and randomly divided into control group (FiO2: = 21%). hyperoxia group ( FiO2: > 85%) and hyperioxia + glutamine (GLN) group (FiO2: > 85%) (n=30). The rats in hyperioxia group and hyperioxia + GLN groups were used to establish the models of hyperoxia lung injury (HALI). The rats in hyperoxia+ GLN group were intraperitoneally injected with 0. 75 g • kg-1 • d-1 GLN from the first day of experiment, and the rats in other two groups were abdominally injected with the same volume of normal saline. The body weights, water contents in the lung tissue of the neonatal rats in various groups on the 3rd. 7th. and 14th days of the experiment were measured. I IF staining was used to determine the morphology of lung tissue of the rats in various groups; ELISA was used to detect the levels of interleukin-6 (IL-6)∗ interleukin-1|ß (IL-lf3) and tumor necrosis factor-a (TNF-a) in the lung tissue homogenate of the rats in various groups. Results: Compared with control group at the same time, the weights of the neonatal rats in hyperoxia group were significantly decreased on the 3rd. 7th and 14th days ( P∗CO. 05); the body weights of neonatal rats in hyperoxia + GLN group were significantly higher than those in hyperoxia group at the same time (P<0. 05). On the 3rd. 7th. and 14th days, the water contents of lung tissue of the rats in hyperoxia group were higher than those in control group at the same time ( P< 0. 05). and the difference was gradually increased with the prolongation of time; the water contents of lung tissue of the rats in hyperoxia • GLN group were significantly lower than those in hyperoxia group ( P
ABSTRACT
Bronchopulmonary dysplasia (BPD) is a chronic lung disease caused by various physical and chemical factors,which causes immature lung injury and abnormal repair after injury.In recent years,BPD has become one of the most difficult problems in neonatal intensive care unit.Notch signaling pathway is a conservative pathway that plays a regulatory role in embryonic development.Notch signaling pathways have a wide range of biological effects.By mediating cell-to-cell interactions,Notch signals can finely regulate the growth,development and apoptosis of cells.This article reviews the relationship between Notch signaling pathway and BPD in lung development,hyperoxia-induced lung injury and lung regeneration.
ABSTRACT
Objective To investigate the effects of Rapamycin and mammalian target of rapamycin - small in-terfering RNA (mTOR siRNA)on the proliferation,apoptosis and collagen Ⅰ(COLⅠ),collagen Ⅲ(COLⅢ)and fi-bronectin(FN)in premature rats lung fibroblasts exposed to hyperoxia. Methods 900 mL/ L volume fraction of oxygen was used to establish hyperoxia - damaged cell models,and the premature rats lung fibroblasts were divided into air control group,hyperoxia group,hyperoxia + rapamycin group and mammalian target of rapamycin - small interfering RNA transfection group. Cell proliferation was assessed by using 3 -(4,5 - Dimethylthiazol - 2 - yl)- 2,5 - dipheny-ltetrazolium bromide assay. Apoptosis were detected by Annexin V - FITC and propidium lodide (PI)double staining. The expressions of COLⅠ,COLⅢ and fibronectin was assessed by using enzyme linked immunosorbent assay and Bcl - 2,P53 and pro - fibrotic factors of connective tissue growth factor(CTGF)and transforming growth factor β(TGF - β)by using Western blot. Results Compared with the air control group,the proliferation of lung fibroblasts decreased and the apoptosis increased in the hyperoxia group,while the contents of COLⅠ(28. 30 ± 0. 53 vs. 17. 43 ±0. 37),COLⅢ(27. 86 ± 1. 02 vs. 17. 43 ± 0. 37)and fibronectin(32. 87 ± 0. 42 vs. 21. 57 ± 0. 47),P53(0. 810 ± 0. 119 vs. 0. 160 ± 0. 018),TGF - β(0. 580 ± 0. 108 vs. 0. 210 ± 0. 008)and CTGF(0. 590 ± 0. 017 vs. 0. 220 ± 0. 007)were also increased but the expression of Bcl - 2(0. 150 ± 0. 004 vs. 0. 600 ± 0. 130)protein was decreased, and the differences were all statistically significant (all P < 0. 01). Compared with the hyperoxia group,the proliferation of lung fibroblasts was increased in the hyperoxia + rapamycin group,but the apoptosis was decreased,the contents of COLⅠ(23. 17 ± 0. 60 vs. 28. 30 ± 0. 53),COLⅢ(17. 09 ± 0. 58 vs. 27. 86 ± 1. 02)and fibronectin(28. 11 ± 0. 68 vs. 32. 87 ± 0. 42),P53(0. 430 ± 0. 008 vs. 0. 810 ± 0. 119),TGF - β(0. 380 ± 0. 008 vs. 0. 580 ± 0. 108)and CTGF (0. 040 ± 0. 006 vs. 0. 590 ± 0. 017)were decreased while the expression of Bcl - 2(0. 290 ± 0. 009 vs. 0. 150 ± 0. 004) protein was increased,and the differences were all statistically significant (all P < 0. 01). In the mTOR siRNA transfec-tion group,compared with the hyperoxia + rapamycin group,the proliferation of lung fibroblasts was increased,but the apoptosis was decreased;the contents of COLⅠ(15. 71 ± 0. 34 vs. 23. 17 ± 0. 60),COLⅢ (13. 85 ± 1. 36 vs. 17. 09 ± 0. 58)and fibronectin(20. 18 ± 0. 28 vs. 28. 11 ± 0. 68),P53(0. 300 ± 0. 006 vs. 0. 430 ± 0. 008),TGF - β(0. 150 ± 0. 002 vs. 0. 380 ± 0. 008)and CTGF(0. 140 ± 0. 004 vs. 0. 040 ± 0. 006)were decreased while the expression of Bcl - 2 (0. 460 ± 0. 012 vs. 10. 290 ± 0. 009)protein was increased,and the differences were all statistically significant (all P < 0. 01). Conclusion Rapamycin and mTOR siRNA can protect lung injury caused by hyperoxia and have a certain inhibitory effect on pulmonary fibrosis,and mTOR siRNA effect is more obvious,so the mechanism may be through the inhibition of mTOR signaling pathway.
ABSTRACT
To investigate the protective effect of retinoicacid (RA) on hyperoxic lung injury and the role of RA as a modulator on mitogen-activated protein kinases (MAPKs), gastation 21 d SpragueDawley (SD) fetuses (term=22d) were delivered by hysterotomy. Within 12-24 h of birth,premature rat pups were randomly divided into 4 groups (n=12 each): air-exposed control group (group Ⅰ); hyperoxia-exposed group ( group Ⅱ), air-exposed plus RA group (group Ⅲ ), hyperoxia-exposed plus RA group (group Ⅳ). Group Ⅰ ,Ⅲ were kept in room air, and group Ⅱ , Ⅳwere placed in 85 % oxygen. The pups in groups Ⅲ and Ⅳ were intraperitoneally injected with RA (500 μg/kg every day). All lung tissues of premature rat pups were collected at the 4th day after birth. Terminal transferase d-UTP nick end labeling (TUNEL) staining was used for the detection of cell apoptosis. The expression of PCNA was immunohistochemically detected. Western blot analysis was employed for the determination of phosphorylated and total nonphosphorylated ERKs,JNKs or p38. Our results showed that lungs from the pups exposed to hyperoxia for 4 d exhibited TUNEL-positive nuclei increased markedly throughout the parenchyma (P＜0.01),and decreased significantly after RA treatment (P＜0.01). The index of PCNA-positive cells was significantly decreased (P＜0.01), and was significantly increased by RA treatment (P＜0.01).The air-space size was significantly enlarged, secondary crests were markedly decreased in hyperoxia-exposed animals. RA treatment improved lung air spaces and secondary crests in air-exposed pups, but had no effect on hyperoxia-exposure pups. Western blotting showed that the amounts of JNK, p38 and ERK proteins in hyperoxia-exposure or RA-treated lung tissues were same as those in untreated lung tissues (P＞0.05), whereas activation of these MAPKs was markedly altered by hyperoxia and RA. After hyperoxia exposure, p-ERK1/2, p-JNK1/2 and p-p38 were dramatically increased (P＜0.01), whereas p-JNK1/2 and p-p38 were markedly declined and p-ERK1/2 was further elevated by RA treatment (P＜0.01). It is concluded that RA could decrease cellapoptosis and stimulate cell proliferation under hyperoxic condition. The protection of RA on hyperoxia-induced lung injury was related to the regulation of MAP kinase activation.