Adenovirus-delivered angiopoietin-1 ameliorates phosgene-induced acute lung injury via inhibition of NLRP3 inflammasome activation.

OBJECTIVE: Angiopoietin-1 (Ang1) is reported to have the ability to attenuate endothelial permeability and inflammation during the stress condition and is considered to play a critical role in vascular stabilization. The aim of this study was to investigate the mechanisms involved in the protective effects of adenovirus-delivered Ang1 in phosgene-induced acute lung injury (ALI). METHODS: ALI was induced in rats by phosgene exposure at 8.33 g/m3 for 5 min, followed by an intravenous injection of adenovirus-Ang1 (Ad/Ang1). The histologic changes of the lung were evaluated with H&E staining. The levels of cytokines in the serum and bronchoalveolar lavage fluid (BALF) were determined by ELISA. NLRP3 inflammasome activation was assessed with immunohistochemistry, RT-PCR, Western blotting and TUNEL staining. RESULTS: Histologic analyses suggested that reduced severity in phosgene-induced ALI with Ad/Ang1 treatment. Reduced levels of IL-1ß, IL-18 and IL-33 were found in both serum and BALF samples from Ad/Ang1-treated ALI rats induced by phosgene. Moreover, immunohistochemistry analysis revealed that Ad/Ang1 treatment inhibited the NLRP3 inflammasome activation. Decreased mRNA and protein levels of NLRP3 and caspase-1 were found in phosgene-exposed rats treated with Ad/Ang1. In addition, TUNEL staining indicated a decrease in pyroptosis in phosgene-exposed rats treated with Ad/Ang1. CONCLUSIONS: Ang1 exerts beneficial effects on phosgene-induced lung injury via inhibition of NLRP3 inflammasome activation. Disruption of NLRP3 inflammasome activation might be served as therapeutic modality for the treatment of phosgene-induced ALI.

Adenovirus-delivered angiopoietin-1 suppresses NF-κB and p38 MAPK and attenuates inflammatory responses in phosgene-induced acute lung injury.

Animals exposed to phosgene (Psg) result in acute lung injury (ALI). We have recently reported that angiopoietin-1 (Ang1) reduces inflammation and vascular hyperpermeability in ALI animals. In this study, we examined whether the beneficial effects of adenovirus-delivered Ang1 (Ad/Ang1) on inflammatory responses in Psg-induced ALI rats are due to the suppression of the nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) pathways, which play crucial roles in inflammatory responses in ALI. We demonstrated that Psg increased Ang2 and inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-4 (IL-4), IL-6, IL-8, and IL-10, in the serum and bronchoalveolar lavage fluid of ALI rats, determined by ELISA. Ang1 inhibits pro-inflammatory mediators (TNF-α, IL-6 and IL-8) and has no effect on anti-inflammatory mediators (IL-4 and IL-10). Furthermore, the inhibitory action of Ang1 was mediated by the suppression of the NF-κB and p38 MAPK pathways, leading to the attenuation of inflammatory responses of ALI. Thus, Ad/Ang1 may provide a useful tool for the effective treatment in Psg-induced ALI.

Characteristics of phosgene aspiration lung injury analyzed based on transcriptomics and proteomics.

Background: Phosgene is a chemical material widely used worldwide. No effective method has been developed to reverse its pathological injuries. Some studies have shown that neuronal inflammation in lung tissue is involved, but the specific mechanism has not been reported. Objective: To analyze the expression alterations of whole transcriptome gene sequencing bioinformatics and protein expression profile in lung tissue after phosgene aspiration lung injury (P-ALI) and find the main factors and pathways affecting the prognosis of P-ALI. Methods: Rat models of P-ALI were made by phosgene. Rats were divided into a P-ALI group and a blank group. Hematoxylin-eosin (HE) staining and lung wet/dry ratio measurement were used to evaluate the lung injury. The levels of inflammatory factors were measured by ELISA. High-throughput sequencing was used to measure the expression profile of each gene. Protein expression profiles were determined by label-free relative quantification of the differential proteome. Results: Lung injury such as the disordered structure of alveolar wall and inflammatory factors (IL-1ß, IL-18, and IL-33) were significantly increased in the P-ALI group (p < 0.05). There were 225 differentially expressed lncRNAs, including 85 upregulated and 140 downregulated genes. They were also the genomes with the most significant changes in transcriptome gene expression, mainly constituting cytoplasmic, synaptic structures and transporters, and involved in amino acid and carbon metabolism. There were 42 differentially expressed circRNAs, including 25 upregulated genes and 17 downregulated genes, mainly involved in cell composition, growth, differentiation, and division. There were only 10 differentially expressed miRNAs genes, all upregulated and mainly involved in the inflammatory response pathway. Proteome identification showed 79 differentially expressed proteins. KEGG enrichment analysis showed that it was mainly involved in the N-glycan biosynthesis pathway. Conclusion: We discovered that differentially regulated genes (lncRNAs, circRNAs, and miRNAs) were primarily associated with neuronal reflexes and synaptic signaling, including neurotransmitter transmission, ion signaling pathway conduction, neuronal projection, and synaptic vesicle circulation. They affected inflammatory factors and other metabolic pathways. This finding could be explored in future studies.

Adenovirus-delivered angiopoietin-1 treatment for phosgene-induced acute lung injury.

CONTEXT: Exposure to phosgene can result in an acute lung injury, leading to pulmonary edema and even death. Angiopoietin-1 (Ang1) is a critical factor for vascular stabilization due to its ability to reduce endothelial permeability and inflammation. OBJECTIVE: In this study, the histopathological changes of the lungs after exposure to phosgene and the effect of Ang1 treatment were examined. MATERIALS AND METHODS: Rats were exposed to phosgene gas at 8.33 g/m³ for 5 min. Ang1 overexpressing rats were established by an intravenous injection of adenovirus-Ang1 (Ad/Ang1). The histological changes of the lung were examined by Haematoxylin-Eosin (H&E) staining and fluorescence microscopy. The inferior lobe was used for the determination of the ratio of wet weight to dry weight of the lung. The concentration of cytokines in the serum and bronchoalveolar lavage fluid was determined by enzyme-linked immunosorbent assay. RESULTS: The pathological analysis showed signs of inflammation and edema, evident from a significant increase in the number of leukocytes in bronchoalveolar lavage fluid and the ratio of wet to dry weight of the lungs. The lung injury induced by phosgene was markedly reduced after the injection of Ad/Ang1. The increase of IL-1ß and IL-17 and decrease of vascular endothelial growth factor in the serum and bronchoalveolar lavage fluid of phosgene-exposed animals were abolished by the administration of Ad/Ang1. DISCUSSION AND CONCLUSIONS: Ang1 has the beneficial effects on phosgene-induced lung injury. The adenovirus-delivered Ang1 may have the potential as a novel approach for the treatment of the acute lung injury caused by phosgene gas inhalation in humans.

Early platelet level reduction as a prognostic factor in intensive care unit patients with severe aspiration pneumonia.

Introduction: This study investigates risk factors underlying the prognosis of severe aspiration pneumonia (SAP) in intensive care unit (ICU) patients and attempts to provide early prognosis reference for clinical tasks. Methods: Patients diagnosed with SAP and admitted to the ICU of Jinshan Hospital, Fudan University, Shanghai, China, between January 2021 and December 2021 were recruited in this retrospective cohort study. Clinical data on a patient's general condition, underlying diseases, laboratory indicators, and 90-day outcomes (survival or death) were recorded. Results: Multivariate logistic regression analysis showed that a low platelet count was an independent risk factor affecting the prognosis of death (OR = 6.68, 95% CI:1.10-40.78, ß = 1.90, P = 0.040). Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive value of variables; cut-off values were calculated and the area under the curve was 0.7782 [(95% CI:0.686-0.871), p < 0.001] for the prediction of death at 90 days in all patients. The Kaplan-Meier curve used for survival analysis showed that, compared with the normal platelet group, the overall survival rate of patients with low platelet levels was significantly lower, and the difference was statistically significant [HR = 2.11, (95% CI:1.47-3.03), p = 0.0001, z = 4.05, X 2 = 14.89]. Cox regression analysis, used to further verify the influence of prognostic risk factors, showed that a concurrent low platelet count was the most important independent risk factor affecting the prognosis of SAP (HR = 2.12 [95% CI:1.12-3.99], X2 = 50.95, p = 0.021). Conclusion: These findings demonstrate an association between SAP mortality and platelet levels on admission. Thus, platelet level at admission may be used as a readily available marker for assessing the prognosis of patients with SAP.

[Expression and role of mitogen activated protein kinases signaling pathway in lung injury induced by phosgene].

OBJECTIVE: This study aimed to investigate the expression and role of the mitogen activated protein kinases (ERK1/2, P38, JNK) in phosgene induced lung injury in rats in vivo. METHOD: 30 male wistar rats were randomized into the group as follows, Gas inhalation control group, Phosgene inhalation group, and the following groups of the inhibitors of MAPK, involving SP600125, PD98059 and SB203580, 6 animals in each group, we copy the model of phosgene-induced lung injury, used the directional flow-inhalation device, the air control group inhaled the air, and the intervention groups were given PD98059 (intraperitoneal injection), SB203580 (hypodermic injection), SP600125 (intravenous) respectively before the inhalation of phosgene. The locations and quantities of three subfamilies of MAPKs (ERK1/2, P38, JNK) and p-MAPKs (p-ERK1/2, p-P38, p-JNK) were analyzed by immunohistochemistry and Western Blot analysis respectively; The histopathological changes of lung tissues, the number of neutrophil cells and the W/D were examined. RESULT: There were rare p-ERK1/2, p-P38 and p-JNK positive expression in alveolar and airway epithelial cells in control group. while the positive cells increased strikingly in phosgene inhalation groups, these cells involved in this process mainly included alveolar epithelial cells, air way epithelial cells, pleural mesothelial cells, infiltrative inflammatory cells, interstitium fibrocytes. After the intervention of the specific inhibitor, the positive cells decreased. As Western Blot analysis show, Protein quantities of p-P38 and p-JNK were higher in phosgene inhalation groups than those in control group, and the differences were significant (P < 0.05). Protein quantities of p-ERK1/2, p-P38 and p-JNK were lower in intervention groups than phosgene inhalation group, and the differences were significant (P < 0.05, P < 0.01). The lung injury in phosgene inhalation groups was more severer compared with the control group, the typical pathological characters of acute lung injury were discovered, the increase of the number of neutrophil cells and W/D. After the intervention of the specific inhibitor SP600125 and SB203580, the number of neutrophil cells and W/D reduced, and the differences were significant (P < 0.05, P < 0.01). CONCLUSION: Phosgene inhalation may activate the MAPK signaling pathway, and the expression of the phosphorylation of MAPKs increased, especially the P38 ang JNK. The results may contribute to the lung injury induced by phosgene.

[Protective effect of melatonin in rats with phosgene-induced lung injury].

OBJECTIVE: To investigate the antioxidant effect of melatonin (MT) in the rats with phosgene-induced lung injury and its possible mechanism. METHODS: Fifty male SD rats were equally randomized into phosgene exposure group, air control group, MT treatment group, dexamethasone (DX) treatment group, and negative control group. All groups except the air control group were exposed to 8.33 mg/L phosgene for 5 min, and the MT treatment group, DX treatment group, and negative control group were injected with MT (10 mg/kg), DX (2.5 mg/kg), and 1% ethanol saline (1 ml/kg), respectively, via the caudal vein 1 hour after exposure. The rats were sacrificed 6h later. Then, the wet/dry ratio of the lung, the total protein content and neutrophil count in bronchoalveolar lavage fluid (BALF), and the malonaldehyde (MDA) content and superoxide dismutase (SOD) and myeloperoxidase (MPO) activities in lung homogenate were measured; pathological observation was made on the lung tissue under an optical microscope; the protein expression of inducible nitric oxide synthase (iNOS) and NF-κB in the lung tissue was measured by Western blot. RESULTS: Compared with the air control group, the phosgene exposure group showed significantly increased wet/dry ratio of the lung and total protein content and neutrophil count in BALF (P < 0.01) as well as significantly increased MDA content and MPO activity in the lung tissue (P < 0.05). Compared with the phosgene exposure group, the MT treatment group showed significantly decreased MDA content and MPO activity and significantly increased SOD activity (P < 0.01), and the MT treatment group and DX treatment group showed significantly decreased protein expression of iNOS and NF-κB (P < 0.01). CONCLUSION: MT has protective effect in phosgene-induced lung injury, and its protective mechanism may be associated with scavenging free radicals and inhibiting expression of iNOS and NF-κB.

[Effects of dexamethasone pretreatment on expression of matrix metalloproteinase-9 in rats with acute lung injury induced by phosgene].

OBJECTIVE: To investigate the effects of dexamethasone on expression of matrix metalloproteinase-9 (MMP-9) in rats with acute lung injury induced by phosgene. METHODS: The rats were randomly divided into 3 groups: normal control group that consists of the rats with air exposure, phosgene group that consists of the rats with phosgene exposure and dexamethasone group that consists of the rats with phosgene exposure after 2.5 mg/kg dexamethasone being injected. Wet and dry ratio of the lung (W/D) was calculated, and leukocyte count and total protein content of bronchoalveolar lavage fluid (BALF) were recorded at 2 h after exposure. The concentrations of MMP-9 in the serum and BALF were measured by enzyme-linked immunosorbent assay. The pathologic changes of lung tissues were observed under light microscopy. The immunohistochemistry and the RT-PCR were used to detect the contents of MMP-9 in the lung tissue. RESULTS: Compared with phosgene group, the lung W/D, protein content and WBC count in of BALF dexamethasone group was significantly decreased (P < 0.01). MMP-9 levels of the serum and BALF in dexamethasone group were (4.799 +/- 0.043) microg/L and (15.052 +/- 0.029) microg/L, respectively, which were significantly lower than those [(9.439 +/- 0.100) and (20.640 +/- 0.446) microg/L] in phosgene group (P < 0.01). Compared with phosgene group (2.789 +/- 0.282),the expression level (1.183 +/- 0.260) of lung MMP-9 mRNA in dexamethasone group was significantly lower than that in phosgene group (P < 0.01). Histological experimental results showed the marked hyperemia and thickening of alveolar walls and stroma cells infiltrating and more visible alveolar structure damage of alveolar walls in phosgene group while the alveolar structure and the alveolar walls were clear and slightly thickened with inflammatory cells in dexamethasone group. Immunohistochemical results showed that MMP-9 protein expression levels of lung and bronchus tissues in normal control group and dexamethasone group were weakly positive, which in phosgene group were strongly positive. CONCLUSION: Dexamethasone has a beneficial effects on acute lung injury induced by phosgene in rats due to the inhibiting MMP-9.

[Protective effects of ulinastatin on phosgene-induced acute lung injury and relation to matrix metalloproteinase-9].

OBJECTIVE: To observe the protective mechanism of ulinastatin on mice with acute lung injury induced by exposure to phosgene and its relationship to the expressions of matrix metalloproteinase-9 (MMP-9) in the lung tissues. METHODS: Sixty-four healthy male SD rats were randomly divided into two groups: the experimental group and the control group. 32 rats in the experiment group were randomly subdivided into four groups: rats with phosgene exposure group, rats with phosgene exposure after saline injected group, rats with phosgene exposure after dexamethasone injected group. 32 rats in the control group were randomly subdivided into four groups: rats with air exposure group, pretreated with ulinastatin before air exposure group, pretreated with saline before air exposure group, pretreated with dexamethasone before air exposure group, 8 animals in each group. After pretreated with the same dose of ulinastatin, saline, dexamethasone respectively, 32 rats in the control groups were exposed to the air on the same condition respectively for 5 min. While after pretreated with the same dose of ulinastatin, saline, dexamethasone respectively, 32 rats in the experiment groups were exposed to the phosgene which the concentration was 8.33 mg/L and with 100% purity for 5 min. The lung wet/dry (W/D) weight ratio was calculated, and total protein content and BALF leukocyte count were detected. The immunohistochemistry was used to detect lung tissue protein expression MMP-9 while enzyme-linked immunosorbent method was employed to detect MMP-9 in serum levels and enzyme original gelatinases spectrum method to detect BALF MMP-9 enzyme original content. RESULTS: Compared with A1, A2, A3, A4 group, the lung W/D, BALF of protein content and WBC count in B1 and B2 group rats were significantly increased, and the difference was statistically significant (P < 0.01). There was statistically significant difference in lung W/D, BALF of protein content and white blood cell count between B1,B2 group and the B3 and B4 rats (P < 0.01). Histological experimental results showed marked hyperemia of alveolar walls, thickening in the lungs, alveolar walls and stroma cells infiltrating and more visible alveolar structure damage in B1 and B2 rats while the alveolar structure, the alveolar walls were clear and slightly thickened with inflammatory cells in B3 and B4 rats. Immunohistochemical result showed that the individual rats, lung and bronchus organization MMP-9 protein were weakly positive, B1 and B2 group MMP-9 protein expression was strongly positive,B3 group and the group MMP B4 lung tissue protein expression-9 weakens, restored to the normal lung tissue of weakly positive expression level. ELISA and gelatinases spectrum testing showed B1 and B2 rats, serum MMP-9 enzyme activity and content increased compared with A1, A2, A3, A4 group, the differences were statistically significant (P < 0.01), and B1, B2 group compared with the B3 and serum B4 group MMP-9 enzyme activity and the differences were obviously decreased, with statistically significant difference (P < 0.01). CONCLUSIONS: Ulinastatin has protective effect on phosgene-induced ALL Ulinastatin can inhibit the up-regulation of expression of MMP-9.

NLRP3 gene silencing ameliorates phosgene-induced acute lung injury in rats by inhibiting NLRP3 inflammasome and proinflammatory factors, but not anti-inflammatory factors.

NOD-like receptor protein 3 (NLRP3) is involved in acute lung injury (ALI), but its exact role in phosgene-induced ALI is not clearly understood. The aim of the study is to explore the potential therapeutic effect of NLRP3 inflammasome modulation in the management of phosgene-induced ALI. ALI was induced in rats by phosgene exposure at 8.33 g/m3 for 5 min, 30 hr before intravenous injection of adenovirus-NLRP3 shRNA (Ad/NLRP3-shRNA). The histological changes in the lung were evaluated. Bronchoalveolar lavage fluid (BALF) neutrophils were counted (smear), and protein content was measured using the BCA assay. The wet/dry ratio of lung tissue (W/D) was measured. TUNEL staining for DNA damage was used to indirectly assess pyroptosis. NLRP3 inflammasome was assessed by immunohistochemistry, RT-PCR, western blotting. Cytokines were measured by ELISA. Histological analyses revealed reduced severity in phosgene-induced ALI with Ad/NLRP3-shRNA pretreatment. TUNEL staining indicated decreased pyroptosis in Psg-Ad/NLRP3-shRNA rats. Decreased mRNA and protein levels of NLRP3 and caspase-1 (all P < 0.05), but not ASC (P > 0.05), were found in Psg-Ad/NLRP3-shRNA rats. Immunohistochemistry revealed that Ad/NLRP3-shRNA pretreatment inhibited NLRP3 inflammasome activation. Reduced level of pro-inflammatory interleukin (IL)-1ß, IL-18, IL-33, and tumor necrosis factor (TNF)-α (all P < 0.05), but not of anti-inflammatory IL-4 and IL-10 (all P > 0.05), were found in serum and BALF from Ad/NLRP3-shRNA rats. NLRP3 gene silencing exerts beneficial effects on phosgene-induced lung injury by inhibiting NLRP3 inflammasome activation and pro-inflammatory factors, but not anti-inflammatory factors. Disruption of NLRP3 inflammasome activation might be used as a therapeutic modality for the treatment of phosgene-induced ALI.

MicroRNA-21 is upregulated during intestinal barrier dysfunction induced by ischemia reperfusion.

This study aimed to investigate the expression of miRNA-21 during intestinal barrier dysfunction induced by intestinal ischemia reperfusion. Forty SPF SD rats were divided into 5 groups randomly. Intestinal ischemia-reperfusion injury (IRI) was induced by mesenteric artery occlusion for 1 h and reperfusion for 1 h, and the rats were sacrificed at 1, 3, 6 and 12 h after reperfusion. Fresh intestine tissues were immediately isolated for the measurement of transepithelial electrical resistance (TER). The levels of cytokines, ICAM-1, DAO, iFABP and MPO in serum were determined by ELISA. Intestinal tight junction proteins occludin and claudin-1 were detected by immunofluorescence analysis and Western blot analysis. miR-21 expression in intestinal tissues was measured by RT-PCR. Compared with sham group, the levels of pro-inflammatory cytokines TNF-α and IL-6 and ICAM-1, DAO, iFABP and MPO increased while IL-10 level decreased in intestinal ischemia-reperfusion group. In addition, the levels of intestinal tight junction proteins occludin and claudin-1 decreased while miR-21 level increased in intestinal ischemia-reperfusion group, compared with sham group. In conclusion, miR-21 expression is upregulated during intestinal barrier dysfunction induced by IRI. miR-21 may play an important role in the regulation of intestinal barrier function.

[Effects of phosphorylated mitogen-activated protein kinases on phosgene inhalation-induced lung injury in rats and its relationship with matrix metalloproteinase].

OBJECTIVE: To investigate the effects of phosphorylated mitogen-activated protein kinases (MAPK), including the phosphorylated extracellular signal-regulated protein kinase 1/2 (p-ERK1/2), the phosphorylated protein p38 (p-p38), the phosphorylated c-Jun N-terminal kinase (p-JNK), on phosgene inhalation-induced lung injury and its relationship with matrix metalloproteinase 9 (MMP-9). METHODS: According to the random number table, 30 male Wistar rats were divided into air control group (C), phosgene inhalation group (P), PD98059 (specific inhibitor of ERK1/2) group, SB203580 (specific inhibitor of p38) group, and SP600125 (specific inhibitor of JNK) group, with 6 rats in each group. The number of neutrophils in the bronchoalveolar lavage fluid (BALF) was counted and the lung wet-dry ratio (W/D) was examined. The serum levels of inflammatory factors TNF-α, IL-1ß, IL-6, and IL-8 were determined with ELISA. The protein expressions of p-ERK1/2, p-p38, p-JNK, and MMP-9 in lung tissue were detected with Western blotting. The mRNA level of MMP-9 in lung tissue was detected with real-time fluorescence quantitative PCR. Data were processed with one-way analysis of variance (among groups) and SNK method (paired comparison). RESULTS: Compared with those of group C [respectively (2.0 ± 0.7)×10(4) /mL and 3.7 ± 0.6], the number of neutrophils and W/D of group P [respectively (10.7 ± 1.4)×10(4) /mL and 7.6 ± 0.4] were increased. The number of neutrophils in group SB203580 and group SP600125 was respectively (8.3 ± 1.1)×10(4), (7.9 ± 1.3)×10(4)/mL, with W/D respectively 6.1 ± 1.4, 6.1 ± 0.9, all of which decreased as compared with those of group P (with P values all below 0.01). Compared with those of group C, the levels of TNF-a, IL-1ß, IL-6, and IL-8 of group P were increased, but decreased in group SB203580 and group SP600125 compared with that of group P, though still higher than those of group C, and the differences were statistically significant (P < 0.05 or P<0.01). Protein quantities of p-p38 and p-JNK were higher in group P (respectively 1.19 ± 0.22 and 1.43 ± 0.14) than in group C (respectively 0.76 ± 0.06 and 0.74 ± 0.05). Compared with those of group P, the protein levels of p-ERK1/2 (0.47 ± 0.05) in group PD98059, p-p38 (0.88 ± 0.07) in group SB203580, and p-JNK (0.91 ± 0.07) in group SP600125 were significantly reduced (P < 0.05 or P < 0.01). The protein and mRNA levels of MMP-9 were higher in group P (respectively 2.23 ± 0.18 and 4.93 ± 0.12) than in group C (respectively 1.26 ± 0.14 and 1.80 ± 0.03). The protein and mRNA levels of MMP-9 in group SB203580 (respectively 1.58 ± 0.14 and 2.96 ± 0.09) and group SP600125 (respectively 1.55 ± 0.30 and 3.00 ± 0.13) were lower than those in group P (P < 0.05 or P < 0.01). CONCLUSIONS: The phosgene inhalation can activate the MAPK signaling protein pathway by increasing expressions of p-p38 and p-JNK, which lead to an up-regulation of MMP-9, and this may contribute to the phosgene inhalation-induced lung injury.