Pentoxifylline inhibits phosgene-induced lung injury via improving hypoxia.

Inhalation of high concentrations of phosgene often causes pulmonary edema, which obstructs the airway and causes tissue hypoxia. There is currently no specific antidote. This study was performed to investigate the effect behind pentoxifylline (PTX) treatment for phosgene-induced lung injury in rat models. Rats were exposed to phosgene. The protein levels of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and occludin proteins in lung tissue were determined. The effect of both prophylactic and therapeutic administration of PTX (50 mg/kg and 100 mg/kg) was evaluated. The lung permeability index and HIF-1α protein level increased, the arterial blood oxygenation index (PaO2/FIO2 ratio) and occludin protein level decreased significantly 6 h after phosgene exposure (P < 0.05). PTX exerted protective effects by HIF-1α-VEGF-occludin signaling pathway to some extent. Moreover, prophylactic, but not therapeutic administration of PTX (100 mg/kg), exhibited a significant protective effect. Pretreatment with PTX protected against phosgene-induced lung injury, possibly by inhibiting differential expression of HIF-1α, VEGF, and occludin.

Heterogeneity of T cells and macrophages in chlorine-induced acute lung injury in mice using single-cell RNA sequencing.

OBJECTIVE: Chlorine (Cl2), as an asphyxiant toxicant, induced poisoning incidents and acute lung injury (ALI) occur frequently. The specific pathogenesis of Cl2-induced ALI remains unclear. Immune cells play an important role in the process of lung damage. We used single-cell RNA sequencing (scRNA-seq) technology to explore T cells and macrophages molecular mechanism. METHODS: Female BALB/c mice were exposed to 400 ppm Cl2 for 15 min. scRNA-seq technology was used to observe the heterogeneity of T cells and macrophages. Hematoxylin-eosin (H&E) staining was used to evaluate the degree of lung injury. Immunofluorescence was used to verify the highly expressed genes of our interest. RESULTS: A total of 5316 to 7742 cells were classified into eight different cell types. Several new highly expressed anti-inflammatory and pro-inflammatory genes were found in T cells and macrophages, which were further verified in vitro. Through the pseudotime analysis of macrophages, it was found that the expression of pro-inflammatory and anti-inflammatory genes showed opposite trends in the development of Cl2-induced ALI. This study also mapped T cells-macrophage communication and identified the development of several important receptor-ligand complexes in Cl2-induced ALI. CONCLUSIONS: These findings are worthy of further exploration and provide new resources and directions for the study of Cl2-induced ALI in mice, especially in immune and inflammation mechanisms.

Ethyl pyruvate protects rats from phosgene-induced pulmonary edema by inhibiting cyclooxygenase2 and inducible nitric oxide synthase expression.

Phosgene is a poorly water-soluble gas penetrating the lower respiratory tract which can induce acute lung injury characterized by a latent phase of fatal pulmonary edema. Pulmonary edema caused by phosgene is believed to be a consequence of oxidative stress and inflammatory responses. Ethyl pyruvate (EP) has been demonstrated to have anti-inflammatory and anti-oxidative properties in vivo and in vitro. The potential therapeutic role of EP in phosgene-induced pulmonary edema has not been addressed so far. In the present study, we aim to investigate the protective effects of EP on phosgene-induced pulmonary edema and the underlying mechanisms. Rats were administered with EP (40 mg kg(-1)) and RAW264.7 cells were also incubated with it (0, 2, 5 or 10 µm) immediately after phosgene (400 ppm, 1 min) or air exposure. Wet-to-dry lung weight ratio (W:D ratio), nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production, cyclooxygenase2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, and mitogen-activated protein kinases activities (MAPKs) were measured. Our results showed that EP treatment attenuated phosgene-induced pulmonary edema and decreased the level of NO and PGE(2) dose-dependently. Furthermore, EP significantly reduced COX-2 expression, iNOS expression and MAPK activation induced by phosgene. Moreover, specific inhibitors of MAPKs reduced COX-2 and iNOS expression induced by phosgene. These findings suggested that EP has a protective role against phosgene-induced pulmonary edema, which is mediated in part by inhibiting MAPK activation and subsequently down-regulating COX-2 and iNOS expression as well as decreasing the production of NO and PGE(2).

Diffusion simulation and risk assessment model establishment of chlorine gas leakage based on terrain conditions.

This study researches the impact of terrain factors on chlorine gas diffusion processes based on SLAB model. Simulating the law of wind speed changing with altitude by calculating the real-time speed with vertical height combing actual terrain data, and integrating the influence of terrain on wind speed by using Reynolds Average Navier-Stokes (RANS) algorithm, K-turbulence model, and standard wall functions, then plotting the gas diffusion range in the map with terrain data according to the Gaussian-Cruger projection algorithm and dividing the hazardous areas according to the public exposure guidelines (PEG). The accidental chlorine gas releases near Lishan Mountain, Xi'an City, were simulated by the improved SLAB model. The results show that there are obvious differences analyzing contrastively the endpoint distance and area of chlorine gas dispersion under real terrain condition and ideal condition at different times; it can be found that the endpoint distance of the real terrain conditions is 1.34 km shorter than that of the ideal conditions at 300 s with terrain factors, and also the thermal area is 3,768,026m2 less than that of the ideal conditions. In addition, it can predict the specific number of casualties within different levels of harm at 2 min after chlorine gas dispersion, and casualties are constantly changing over time. The fusion of terrain factors can be used to optimize the SLAB model, which is expected to provide an important reference for effective rescue.

Protective effects of pentoxifylline against chlorine-induced acute lung injury in rats.

OBJECTIVE: Chlorine is a chemical threat agent that can be harmful to humans. Inhalation of high levels of chlorine can lead to acute lung injury (ALI). Currently, there is no satisfactory treatment, and effective antidote is urgently needed. Pentoxifylline (PTX), a methylxanthine derivative and nonspecific phosphodiesterase inhibitor, is widely used for the treatment of vascular disorders. The present study was aimed to investigate the inhibitory effects of PTX on chlorine-induced ALI in rats. METHODS: Adult male Sprague-Dawley rats were exposed to 400 ppm Cl2 for 5 min. The histopathological examination was carried out and intracellular reactive oxygen species (ROS) levels were measured by the confocal laser scanning system. Subsequently, to evaluate the effect of PTX, a dose of 100 mg/kg was administered. The activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG) and lactate dehydrogenase (LDH) were determined by using commercial kits according to the manufacturer's instructions. Western blot assay was used to detect the protein expressions of SOD1, SOD2, catalase (CAT), hypoxia-inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF), occludin, E-cadherin, bcl-xl, LC 3, Beclin 1, PTEN-induced putative kinase 1 (PINK 1) and Parkin. RESULTS: The histopathological examination demonstrated that chlorine could destroy the lung structure with hemorrhage, alveolar collapse, and inflammatory infiltration. ROS accumulation was significantly higher in the lungs of rats suffering from inhaling chlorine (P<0.05). PTX markedly reduced concentrations of MAD and GSSG, while increased GSH (P<0.05). The protein expression levels of SOD1 and CAT also decreased (P<0.05). Furthermore, the activity of LDH in rats treated with PTX was significantly decreased compared to those of non-treated group (P<0.05). Additionally, the results also showed that PTX exerted an inhibition effect on protein expressions of HIF-1α, VEGF and occludin, and increased the level of E-cadherin (P<0.05). While the up-regulation of Beclin 1, LC 3II/I, Bcl-xl, and Parkin both in the lung tissues and mitochondria, were found in PTX treated rats (P<0.05). The other protein levels were decreased when treated with PTX (P<0.05). CONCLUSION: PTX could ameliorate chlorine-induced lung injury via inhibition effects on oxidative stress, hypoxia and autophagy, thus suggesting that PTX could serve as a potential therapeutic approach for ALI.

Single-cell transcriptomes reveal heterogeneity of chlorine-induced mice acute lung injury and the inhibitory effect of pentoxifylline on ferroptosis.

To investigate the effect of pentoxifylline (PTX) on Chlorine (Cl2)-induced acute lung injury (ALI) by single-cell RNA sequencing (scRNA-seq). Female BALB/c mice were exposed to Cl2 at 400 ppm for 15 min. H&E staining was used to observe the degree of lung injury. scRNA-seq was conducted to analysis of normal and Cl2-exposed mice lung tissues. Immunofluorescence was used to observe genes of interest. Thirty-two mice were randomly divided into four groups: Control, Cl2, Cl2+Fer-1, Cl2+PTX. TEM, WB and ELISA were used to detect ferroptosis-related indicators. The 5, 8, 10, 12, 16, 20 clusters were epithelial cells and 4, 15, 18, 19, 21 clusters were endothelial cells. Pseudo-time analysis revealed the differentiation trajectory of epithelial cells and key regulatory genes (Gclc, Bpifa1, Dnah5 and Dnah9) during the process of injury. Cell-cell communication analysis identified several important receptor-ligand complexes (Nrp1-Vegfa, Nrp2-Vegfa, Flt1-Vegfa and Flt4-Vegfa). Ferroptosis were found up-regulated in epithelial and endothelial cells by GSVA analysis. Highly expressed genes to which closely related ferroptosis were found by SCENIC analysis. PTX could significantly decrease the levels of MDA and abnormal high expression of solute carrier family 7 member 11 (SLC7A11, the key transporter of cystine) as well as increase the expression of GSH/GSSG and glutathione peroxidase 4 (GPX4) (p < 0.05). This study revealed novel molecular features of Cl2-induced ALI. PTX may be a potential specific drug by inhibiting the process of ferroptosis in epithelial and endothelial cells.

Inhaled nitric oxide aggravates phosgene model of acute lung injury.

The principal acute mode of action of inhaled phosgene gas is related to an increase alveolar fluid exudation under pathologic conditions. This paper considers some aspects in modeling phosgene-induced acute lung injury (ALI) in an acute rat bioassay and whether edema formation can be modulated by inhaled nitric oxide (iNO). Protein analysis in bronchoalveolar lavage (BAL) fluid is amongst the most sensitive method to quantify the phosgene-induced non-cardiogenic, pulmonary high-permeability edema following acute inhalation exposure. Maximum concentrations in BAL-protein occur within one day postexposure, typically within a latency period up to about 15 h as a consequence of an increasingly exhausted lymphatic drainage. An almost similar sensitivity was given by the functional endpoint 'enhanced pause (Penh)' when measured by non-invasive whole-body barometric plethysmography over a time period of 20 h. The magnitude of edema formation follows a concentration x time (C¹xt) relationship, although animal model-specific deviations may occur at very short exposure durations (1-20 min) due to a rodent-specific, reflexively induced transient decreased ventilation. This has to be accounted for when simulating accidental exposure scenarios to study the mechanisms involved in pharmacological modulation of fluid transport in this type of ALI. Therefore, a special focus has to be given to the dosimetry of inhaled phosgene, otherwise any change in effect magnitude, as a result of under-dosing of phosgene, may be misconceived as promising therapy. This study demonstrates that accidental exposures can be modeled best in rats by exposure durations of at least 20-30 min. Lung function measurements (Penh) show that pathophysiological effects appear to occur concomitant with the exposure to phosgene; however, its full clinical manifestation requires a gross imbalance of pulmonary fluid clearance. When applying this concept, post-phosgene exposure iNO at 1.5 ppm × 6 h or 15 pm × 20 h led to an aggravation of edema formation while L-NAME, a non-selective inhibitor of nitric oxide synthase, led to attenuation. Ethyl pyruvate, given either prophylactically or therapeutically, was ineffective.

Antidiabetic effect of oleanolic acid: a promising use of a traditional pharmacological agent.

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia. Although the clear mechanisms of DM and insulin resistance are still to be cleared, it has been well documented that reactive oxygen species (ROS) play a pivotal role in DM and multiple types of insulin resistance. For the past few years, natural substances have been shown to have the potential to treatment DM. Attention has been especially focused on plants rich in triterpenoids, which generally show antioxidant and antiglycation effect. In our previous studies, it was shown that oleanolic acid (OA), a natural triterpenoid and an aglycone of many saponins, is a potent antioxidant acting as not only a free radical-scavenger through direct chemical reactions but also as a biological molecule, which may enhance the antioxidant defenses. The present study aimed to investigate the potential antidiabetic effect of OA. Oleanolic acid showed a significant blood glucose-lowering and weight-losing effect in diabetic animals induced by streptozotocin (STZ). In the insulin resistant model, it was also shown that OA may promote insulin signal transduction and inhibit oxidative stress-induced hepatic insulin resistance and gluconeogenesis, in which process the phosphorylation of ERK and the protective effect on mitochondrial function may be involved. These findings may significantly better the understanding of the pharmacological actions of OA and advance therapeutic approaches to DM.

Pentoxifylline inhibits intercellular adhesion molecule-1 (ICAM-1) and lung injury in experimental phosgene-exposure rats.

Phosgene inhalation results in acute lung injury (ALI) mostly, pulmonary edema and even acute respiratory distress syndrome, but there is no specific antidote. Inflammatory cells play an important role in the ALI caused by phosgene. Intercellular adhesion molecule-1 (ICAM-1) is a critical factor for inflammatory organ injury. We hypothesized that pentoxifylline (PTX), an inhibitor of leukocyte activation, would have a protective effect on experimental phosgene-induced lung injury rats by inhibiting ICAM-1. To prove this hypothesis, we used rat models of phosgene (400 ppm x 1 min)-induced injury to investigate: (1) the time course of lung injury (control 1, 3, 6, 12, 24, and 48 h group), including pathological changes in hematoxylin and eosin staining and transmission electron microscope, myeloperoxidase (MPO) activity by colorimetric method and ICAM-1 protein level detected by western blot, (2) At 3 h after phosgene exposure, protective effects of different dosages of PTX (50 mg/kg and 100 mg/kg) administration were evaluated by MPO activity, ICAM-1 differential expression and WBC count in bronchoalveolar lavage fluid. The results showed that inflammatory cells emerged out of lung blood vessels at 3 h after phosgene exposure. The MPO activity of lung tissue increased significantly from 3 to 48 h after phosgene exposure (P < 0.05) and ICAM-1 expression presented a similar change, especially at 3 h and 24 h (P < 0.05). After pretreatment and treatment with PTX (100 mg/kg), significant protective effects were shown (P < 0.05). These data supported our hypothesis that PTX reduced phosgene-induced lung injury, possibly by inhibiting ICAM-1 differential expression.

N-acetylcysteine attenuates phosgene-induced acute lung injury via up-regulation of Nrf2 expression.

Previous studies indicated that oxidative stress was involved in phosgene-induced acute lung injury (ALI) and many antioxidants had been used to prevent ALI. N-acetylcysteine (NAC) had been used to protect ALI induced by various types of oxidative stress. Considering the limited information of NAC on phosgene-induced ALI, the purpose of this study was to elucidate the molecular mechanisms of phosgene-induced ALI and the protective effects of NAC. This study discovered that intraperitoneal administration of NAC significantly alleviated phosgene-induced pulmonary edema, as confirmed by decreased lung wet to dry weight ratio and oxidative stress markers. The content of l-gamma-glutamyl-l-cysteinyl-glycine (glutathione; GSH) and the ratio of the reduced and disulfide forms (GSH/GSSG), significant indicators of the antioxidative ability, were apparently inhibited by phosgene exposure. However, both indicators could be reversed by NAC administration, indicating that dysregulation of redox status of glutathione might be the cause of phosgene-induced ALI. The nuclear factor (NF)-E2-related factor 2 (Nrf2), which has been proven to up-regulate the expression of glutathione reductase (GR), was obviously decreased by phosgene exposure. However, NAC administration elevated Nrf2 expression significantly. In conclusion, these data provided the first evidences showing that it was the transcriptional factor Nrf2 that connected phosgene-induced ALI with GSH metabolism. NAC protected against oxidative stress through acting on this newly disclosed Nrf2/GR/GSH pathway, by which NAC elevated the biosynthesis of protective GSH to repair and reconstitute the defense system destroyed by phosgene.

Correlation between sPLA2-IIA and phosgene-induced rat acute lung injury.

Secreted phospholipase A(2) of group IIA (sPLA(2)-IIA) has been involved in a variety of inflammatory diseases, including acute lung injury. However, the specific role of sPLA(2)-IIA in phosgene-induced acute lung injury remains unidentified. The aim of the present study was to investigate the correlation between sPLA(2)-IIA activity and the severity of phosgene-induced acute lung injury. Adult male rats were randomly exposed to either normal room air (control group) or a concentration of 400 ppm phosgene (phosgene-exposed group) for there are 5 phosgene-exposed groups altogether. For the time points of 1, 3, 6, 12 and 24 h post-exposure, one phosgene-exposed group was sacrificed at each time point. The severity of acute lung injury was assessed by Pa(O2)/F(IO2) ratio, wet-to-dry lung-weight ratio, and bronchoalveolar lavage (BAL) fluid protein concentration. sPLA(2)-IIA activity in BAL fluid markedly increased between 1 h and 12 h after phosgene exposure, and reached its highest level at 6 h. Moreover, the trend of this elevation correlated well with the severity of lung injury. These results indicate that sPLA(2)-IIA probably participates in phosgene-induced acute lung injury.

The dysfunction of ATPases due to impaired mitochondrial respiration in phosgene-induced pulmonary edema.

Phosgene is a toxic gas that is widely used in modern industry, and its inhalation can cause severe pulmonary edema. There is no effective clinical treatment because the mechanism of phosgene-induced pulmonary edema still remains unclear. Many studies have demonstrated that the Na(+)/K(+)-ATPase plays a critical role in clearing pulmonary edema and the inhibition of Na(+)/K(+)-ATPase protein expression has been found in many other pulmonary edema models. In the present study, after the mice were exposed to phosgene, there was serious pulmonary edema, indicating the dysfunction of the ATPases in mice. However, in vitro enzyme study showed that there were increases in the activities of the Na(+)/K(+)-ATPase and Ca(2+)-ATPase. Further investigation showed that the ATP content and mitochondrial respiratory control ratio (RCR) in the lungs decreased significantly. The oxidative stress product, malondialdehyde (MDA), increased while the antioxidants (GSH, SOD, and TAC) decreased significantly. These results indicate that mitochondrial respiration is the target of phosgene. The dysfunction of ATPases due to impaired mitochondrial respiration may be a new mechanism of phosgene-induced pulmonary edema.

Time course for expression of VEGF and its receptor and regulator levels of contraction and relaxation in increased vascular permeability of lung induced by phosgene.

Acute lung injury (ALI) induced by phosgene increases risk of serious edema and mortality. Increased permeability of the microvascular endothelium is implicated in the progression of ALI, but the processing interaction and time course activity of the vascular regulators in exudation are still not understood. The main aim of this study was to investigate the time course and potential role for vascular endothelial growth factor (VEGF), its receptors, and some vascular function regulators related to increased vascular permeability of lung induced by phosgene. Sprague Dawley rats were randomly divided into seven groups according to time post phosgene exposure (control, and 1, 3, 6, 12, 24, and 48 h groups). Lung tissue was removed to evaluate VEGF isoforms, fms-like tyrosine kinase receptor 1 (Flt-1), and kinase insert domain containing region (KDR/Flk-1) by reverse-transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Blood samples were collected for measurement of plasma endothelin-1 (ET-1) and nitric oxide (NO) level. The results showed that the mRNA and protein expression profile of the VEGF system after phosgene exposure was time dependent. The VEGF system expression in lung tissue was related closely to the level of ET-1 and NO. In conclusion, increased permeability of the lung microvascular endothelium induced by phosgene was primarily a result of differential expression of VEGF and its receptors, and was related to the level of ET-1 and NO. The results suggest that the cooperation of VEGF system, ET-1, and NO plays a critical role, and all those parameters emerge as time dependent in the early phase of the permeability process induced by phosgene exposure.

[Speciation analysis of trace elements Cu, Fe and Zn in serum by flame atomic absorption spectrophotometry].

Since biological functions of the elements are generally different, depending on their chemical forms, chemical speciation analysis is really important in metallomics research. Thus, multielement analysis and chemical speciation of the elements in serum were carried out in the present work. A hyphenated technique was developed for high-throughput speciation analysis of the copper, iron and zinc in serum by molecular biology technology and flame atomic absorption spectrophotometry (AAS). Here, Cu, Fe and Zn in serum were classifyied as the forms of combination and non-combination. The serum protein was precipitated by 60% concentration of ethanol under hypothermy. The forms of combination of Cu, Fe and Zn in serum which combined with proteins were in precipitations, and the forms of non-combination of Cu, Fe and Zn in serum, which were free ions, were in supernatant. The total amount of Cu, Fe and Zn in serum and the amount of the forms of non-combination of Cu, Fe and Zn were analyzed by AAS. The amount of the forms of combination of Cu, Fe and Zn was obtained by calculation. The detection limit of Cu in serum by the method is around and 9.84 x 10(-3) microg x mL(-1). For Fe and Zn, the detection limit is about 2.76 x 10(-2) microg x mL(-1) and 1.06 x 10(-3) microg x mL(-1), respectively. The percentage recovery of trace elements Cu, Fe and Zn by the proposed procedure is in the range 95.0%-101.0%, 95.0%-102.0% and 95.0%-103.0%, respectively. The relative standard deviation (RSD) of trace elements Cu, Fe and Zn in the serum is in the range 1.88%-2.26%, 0.56%-1.59% and 0.34%-1.36%, respectively. Speciation of trace elements Cu, Fe and Zn in the serum of SD rat were analyzed by the method.

Nano-oleanolic acid alleviates metabolic dysfunctions in rats with high fat and fructose diet.

Obesity, diabetes and related metabolic disorders are among the top prevalent metabolism-related diseases with increasing threat to human health throughout the world. Oleanolic acid (OA) is a natural triterpenoid and an aglycone of many saponins possessing anti-diabetic, antioxidant, hypolipidemic and anti-inflammatory activities. A nano-formulation of OA was recently developed to evaluate the efficiency of nano-OA in the treatment of insulin-resistance and metabolic disorders in high fat and fructose (HFF) diet-fed rats. This study further identified that nano-OA could reduce the increase of body weights, serum insulin, insulin sensitivity index, serum triglycerides, and cholesterol in HFF-fed rats. In consistence, nano-OA was able to attenuate HFF diet-induced lipid accumulation in the liver and improve the structural integrity of mitochondria and endoplasmic reticulum in liver and pancreas in animals fed with HFF diet. In addition, nan-OA can efficaciously mitigate the increase of levels of malondialdehyde (MDA) and nitric oxide (NO), and serum superoxide dismutase (SOD) and catalase (CAT) activities in blood samples. The beneficial effects of nano-OA was further evidenced to be superior to OA formulated in arabic gum and rosiglitazone treatment. Together, this study provides the evidence that nano-OA can effectively improve HFF diet-induced metabolic dysfunctions in rats by improving its bioavailability and pharmacodynamic properties and thus nano-OA may be a potentially efficient agent to treat obesity-related diabetes and metabolic disorders.

Apoptosis of ATII cells in mice induced by phosgene.

Phosgene inhalation can induced pulmonary edema formation. The purpose of this study was to investigate cell of apoptosis in pulmonary edema mice induced by phosgene. Fifty-two BALB/c mice were random divided into a negative group and a positive group with 26 mice in each. Mice were exposed for 5 min to air and phosgene in the negative group and in the positive one, respectively. The dose of phosgene was 539 ppm. After 4 h of exposure, all mice were anesthetized. Lungs were analyzed for lung wet/dry weight ratio and pathological alternation. The method of isolation and culture of alveolar type II cells (ATII cells) was established to observe their apoptosis by electron microscope and flow cytometry. Apoptosis of lung cells was observed by DNA gel electrophoresis and TUNEL. The lung wet/dry weight ratio was significantly higher in the positive group (6.42 +/- 1.00) than in the negative group (4.25 +/- 0.47, p < 0.05). A large amount of fluid effusion was observed in the alveolus of mice induced by phosgene. Alveolar type II cells were identified by tannic acid staining and electron microscope. The apoptotic signs in alveolar type II cells, alveolar type I cells, eosinophils, macrophages, symphocytes, and ciliated cells were viewed under electron microscope in positive group. The ratio of apoptosis cells (40.26 +/- 7.74) in positive was higher than that (1.58 +/- 1.01, p < 0.001) in the negative group by flow cytometry. DNA ladder alternation was seen through DNA gel electrophoresis. Apoptosis of epithelia and vascular endothelia in lung were found by TUNEL. These results indicate that there is success in establishing a model of pulmonary edema and method of isolation and culture of AT II cells in BALB/c mice. Phosgene can induce apoptosis of cells in the lungs of BALB/c mice, and this indicates that pulmonary edema is related to apoptosis of lung cells in mice, induced by phosgene.

[Apoptosis of pulmonary epithelial cells and endothelial cells in mice exposed to phosgene].

OBJECTIVE: To study apoptosis of pulmonary epithelial cells and endothelial cells in mice with pulmonary edema induced by phosgene exposure. METHODS: Thirty-two mice were divided into normal group and phosgene group with 16 mice in each group. The mice in phosgene group were exposed to phosgene (11.9 mg/L) for 5 min and those in the control group to air. Four hours after exposure, alveolar type II cells were isolated and cultured to observe their apoptosis by electron microscope and flow cytometry. The lung tissues were also taken for DNA gel electrophoresis and TUNEL assay. RESULTS: Apoptotic bodies were observed in alveolar type II cells under electron microscope in phosgene group, which had higher cell apoptosis rate than the control group [(40.26+/-7.74)% vs (1.58+/-1.01)%, P<0.001] as determined by flow cytometry. Ladder-like DNA fragmentation pattern was observed in DNA gel electrophoresis in phosgene group with apoptosis of the pulmonary epithelial and endothelial cells observed by TUNEL. CONCLUSIONS: Phosgene can induce pulmonary epithelial and endothelial cell apoptosis in mice, suggesting that the mechanism of phosgene-induced pulmonary edema involves apoptosis of the lung cells.

[Observation on the protective effect of hyperoxia solution on the acute lung injury caused by phosgene poisoning.].

OBJECTIVE: To study the protective effect of hyperoxia solution on acute lung injury caused by phosgene poisoning by observing the changes of PaO2 and malondialdehyde (MDA) contents, superoxide dismutase (SOD) activity in serum and Glutathione (GSH/GSSG) contents in lung tissues. METHODS: The rabbits were divided into normal control group, hyperoxia solution (H0) and balance salt (BS) groups. Group HO and Group BS inhaled phosgene and the former was given intravenously hyperoxia solution (which was replaced by balance salt solution in Group BS). The content of MDA and the activity of SOD in serum were observed at different time points, the amount of GSH and GSSG in lung tissue were also measured. RESULTS: (1) The serum MDA contents increased and PaO2, SOD activity decreased significantly in Group HO and Group BS along with time increasing as compared with control group. The contents of GSH in lung tissue decreased in two groups compared with that in control group, however the contents of GSSG ascended instead. (2) At 3 and 8 h of the experiment, PaO2 of Group HO [(9.91 +/- 0.49), (9.15 +/- 0.46) mm Hg respectively] were significantly higher than those of Group BS [(9.03 +/- 0.76), (8.11 +/- 0.57) mm Hg respectively] (P < 0.01). The contents of MDA of Group HO (3.66 +/- 0.35), (5.31 +/- 0.15) micromol/L respectively] were lower than those of Group BS [(4.32 +/- 0.26), (7.4 +/- 0.33) micromol/L respectively] (P < 0.01). SOD activity in Group HO [(237.37 +/- 29.96), (208.10 +/- 18.80) NU/ml respectively] were higher than those of Group BS [(195.02 +/- 21.44), (144.87 +/- 21.26) NU/ml respectively] (P < 0.05 or P < 0.01). The content of GSSG lung tissue in Group HO (423.67 +/- 38.21) micromol/L were lower than those of Group BS (523.85 +/- 43.14) mol/L (P < 0.01). There were no significant differences in the content of GSH in lung tissues between Group HO and group BS. CONCLUSION: Hyperoxia solution can reduce acute lung injury of rabbits following phosgene poisoning.

Hydrogen peroxide modulates the proliferation/quiescence switch in the liver during embryonic development and posthepatectomy regeneration.

AIMS: The liver undergoes marked changes in the rate of proliferation during normal development and regeneration through the coordinated activity of numerous signaling pathways. Little is known, however, about the events that act upstream of these signaling pathways. Here, we explore the modulatory effects of hydrogen peroxide (H2O2) on these pathways in the context of liver development and regeneration. RESULTS: We show that H2O2 production during liver development and after partial hepatectomy is tightly regulated in time by specific H2O2-producing and scavenging proteins and dose dependently triggers two distinct pathways. Sustained elevated H2O2 levels are required for the activation of ERK signaling and trigger a shift from quiescence to proliferation. Contrastingly, sustained decreased H2O2 levels are required for the activation of p38 signaling and trigger a shift from proliferation to quiescence. Both events impact the cyclin D and Rb pathways and are involved in liver development and regeneration. Pharmacological lowering of H2O2 levels reduces the extent of fetal hepatocyte proliferation and delays the onset of liver regeneration. Chemical augmentation of H2O2 levels in adult hepatocytes triggers proliferation and delays the termination of liver regeneration. INNOVATION: Our results challenge the traditional view of H2O2 as a deleterious stressor in response to liver damage and identify a novel role of endogenous H2O2 in liver development and regeneration. CONCLUSIONS: Endogenous H2O2 production is tightly regulated during liver development and regeneration. H2O2 constitutes an important trigger for the proliferation and quiescence transition in hepatocytes via the concentration-dependent activation of the ERK or p38 pathway.

CDK1-Mediated SIRT3 Activation Enhances Mitochondrial Function and Tumor Radioresistance.

Tumor adaptive resistance to therapeutic radiation remains a barrier for further improvement of local cancer control. SIRT3, a member of the sirtuin family of NAD(+)-dependent protein deacetylases in mitochondria, promotes metabolic homeostasis through regulation of mitochondrial protein deacetylation and plays a key role in prevention of cell aging. Here, we demonstrate that SIRT3 expression is induced in an array of radiation-treated human tumor cells and their corresponding xenograft tumors, including colon cancer HCT-116, glioblastoma U87, and breast cancer MDA-MB231 cells. SIRT3 transcriptional activation is due to SIRT3 promoter activation controlled by the stress transcription factor NF-κB. Posttranscriptionally, SIRT3 enzymatic activity is further enhanced via Thr150/Ser159 phosphorylation by cyclin B1-CDK1, which is also induced by radiation and relocated to mitochondria together with SIRT3. Cells expressing Thr150Ala/Ser159Ala-mutant SIRT3 show a reduction in mitochondrial protein lysine deacetylation, Δψm, MnSOD activity, and mitochondrial ATP generation. The clonogenicity of Thr150Ala/Ser159Ala-mutant transfectants is lower and significantly decreased under radiation. Tumors harboring Thr150Ala/Ser159Ala-mutant SIRT3 show inhibited growth and increased sensitivity to in vivo local irradiation. These results demonstrate that enhanced SIRT3 transcription and posttranslational modifications in mitochondria contribute to adaptive radioresistance in tumor cells. CDK1-mediated SIRT3 phosphorylation is a potential effective target to sensitize tumor cells to radiotherapy.