Alveolar Epithelial Cells ; metabolism ; pathology ; Animals ; Apoptosis ; physiology ; Cell Survival ; physiology ; Cells, Cultured ; Epithelial Cells ; cytology ; physiology ; Genes, bcl-2 ; genetics ; Genes, p53 ; genetics ; Oxidative Stress ; genetics ; Rats

BACKGROUND: Currently, a significant number of miners are involved in mining operations at the Gejiu tin mine in Yunnan. This occupational setting is associated with exposure to dust particles, heavy metals, polycyclic aromatic hydrocarbons, and radioactive radon, thereby significantly elevating the risk of lung cancer. This study aims to investigate the involvement of leptin-mediated extracellular regulated protein kinase (ERK) signaling pathway in the malignant transformation of rat alveolar type II epithelial cells induced by Yunnan tin mine dust. METHODS: Immortalized rat alveolar cells type II (RLE-6TN) cells were infected with Yunnan tin mine dust at a concentration of 200 μg/mL for nine consecutive generations to establish the infected cell model, which was named R₂₀₀ cells. The cells were cultured normally, named as R cells. The expression of leptin receptor in both cell groups was detected using the Western blot method. The optimal concentration of leptin and mitogen-activated protein kinase kinase (MEK) inhibitor (U0126) on R₂₀₀ cells was determined using the MTT method. Starting from the 20th generation, the cells in the R group were co-cultured with leptin, while the cells in the R₂₀₀ group were co-cultured with the MEK inhibitor U0126. The morphological alterations of the cells in each group were visualized utilizing hematoxylin-eosin staining. Additionally, concanavalin A (ConA) was utilized to detect any morphological differences, and an anchorage-independent growth assay was conducted to assess the malignant transformation of the cells. The changes in the ERK signaling pathway in epithelial cells after the action of leptin were detected using the Western blot method. RESULTS: Both the cells in the R group and R₂₀₀ group express leptin receptor OB-R. Compared to the R₂₀₀ group, the concentration of leptin at 100 ng/mL shows the most significant pro-proliferation effect. The proliferation of R₂₀₀ cells infected with the virus is inhibited by 30 μmol/L U0126, and a statistically significant divergence was seen when compared to the control group (P<0.05). Starting from the 25th generation, the cell morphology of the leptin-induced R₂₀₀ group (R₂₀₀L group) underwent changes, leading to malignant transformation observed at the 30th generation. The characteristics of malignant transformation became evident by the 40th generation in the R₂₀₀L group. In contrast, the other groups showed agglutination of P40 cells, and the speed of cell aggregation increased with an increase in ConA concentration. Notably, the R₂₀₀L group exhibited faster cell aggregation compared to the U0126-induced R₂₀₀ (R₂₀₀LU) group. Additionally, the cells in the R₂₀₀L group were capable of forming clones starting from P30, with a colony formation rate of 2.25‰±0.5‰. However, no clonal colonies were observed in the R₂₀₀LU group and R₂₀₀ group. The expression of phosphorylated extracellular signal-regulated kinase (pERK) was enhanced in cells of the R₂₀₀L group. However, when the cells in the R₂₀₀L group were treated with U0126, a blocking agent, the phosphorylation level of pERK decreased. CONCLUSIONS Leptin can promote the malignant transformation of lung epithelial cells infected by mine dust, and the ERK signaling pathway may be necessary for the transformation of alveolar type II epithelial cells induced by Yunnan tin mine dust.
Rats ; Animals ; Alveolar Epithelial Cells/pathology* ; Dust ; Tin/adverse effects* ; Lung Neoplasms/pathology* ; Leptin/adverse effects* ; Receptors, Leptin ; China ; Signal Transduction ; Epithelial Cells/pathology* ; Mitogen-Activated Protein Kinase Kinases/adverse effects*

OBJECTIVETo investigate the effects of curcumin (CUR) on pneumocyte apoptosis and CCAAT/enhancer binding protein homologous protein (CHOP) in pulmonary ischemia/reperfusion injury (PIRI) in mice.

METHODSSixty C57BL/6J mice were randomly allocated into six groups (n = 10): Sham operation group (Sham group), ischemia/reperfusion group (I/R group), ischemia/reperfusion + dimethyl sulfoxide group (DMSO group), ischemia/reperfusion + curcumin pre-treated with respectively 100 mg/kg, 150 mg/kg and 200 mg/kg groups (CUR-100 group, CUR-150 group and CUR-200 group). Left lung tissue of each group was excised after reperfusion for 3 h. Wet lung weight to dry lung weight (W/D) and total lung water content (TLW) were tested. The morphological and ultrastructural changes of lung tissue were observed under light microscope and electron microscope, and index of quantitative evaluation for alveolar damage (IQA) was calculated. The expression levels of CHOP and glucose regulated protein 78 (GRP78) were detected by RT-PCR and Western Blot. Apoptosis index (AI) of lung tissue was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method.

RESULTSCompared with Sham group, the expression levels of CHOP, GRP78 mRNA and protein were all significantly increased (P < 0.05) in I/R group and DMSO group, W/D, TLW, IQA and AI were all notably higher (P < 0.01); morphological and ultrastructural injury in lung tissue were notably observed in I/R group. Compared with DMSO group, the expression levels of GRP78 mRNA and protein were increased higher (P < 0. 05) in CUR-100 group, CUR-150 group, and CUR-200 group, but the expression levels of CHOP mRNA and protein were decreased lower (P < 0.05), W/D, TLW, IQA and AI were also decreased (P < 0.05, P < 0.01); morphological and ultrastructural injury in lung tissue were gradually alleviated in CUR groups.

CONCLUSIONI/R induces excessive unfolded protein response (UPR) in lung tissue, in which CHOP participates in pneumocyte apoptosis, leading to lung injury; CUR has notable effects on lung protection against I/R injury, which may be related to inhibition of apoptosis mediated by CHOP in excessive UPR.

Alveolar Epithelial Cells ; metabolism ; Animals ; Apoptosis ; Curcumin ; pharmacology ; Heat-Shock Proteins ; metabolism ; Lung ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Reperfusion Injury ; metabolism ; pathology ; Transcription Factor CHOP ; metabolism

OBJECTIVETo explore the pathological changes of pulmonary fibrosis induced by SiO2 in rats and pigs.

METHODSThe silicosis models in rats and pigs were established by non-exposure method. The pathologic changes in lung tissues of rats and pigs were observed with HE staining under a light microscopy and under a transmission electron microscopy (TEM), the expression of cytokines was detected by immunohistochemistry.

RESULTS(1) The main pathologic changes of silicosis models in rats and pigs included: in 7 ∼ 15 days after treatment, silica dusts, dust cells, a lot of macrophages, lung epithelial cells, a few neutrophils, macrophage alveolar inflammation and nodules of stage I were found in alveolar space; in 30 ∼ 90 days after treatment, many nodules of stage I-III or IV with lymphocytes infiltration were observed in respiratory bronchioles, alveoli, interlobular septa, the subpleural and around blood vessels and bronchi. (2) The expression levels of CK protein, SP-A protein, CD68, b-FGF, TNF-α, IL-6, TGF-β1, NFKappa/P50, Kappa/P65 and VEGF reduced with exposure time, but still were higher than those of the control. (3) The shed alveolar type I cells, proliferation of alveolar type II cells or macrophages and activated cellular function induced by silica were observed under TEM.

CONCLUSIONThe development of pulmonary fibrosis in silicosis models corresponded with the process from macrophages alveolar inflammation to pulmonary fibrosis.

Animals ; Cytokines ; metabolism ; Disease Models, Animal ; Epithelial Cells ; metabolism ; Female ; Lung ; cytology ; pathology ; Macrophages, Alveolar ; metabolism ; Male ; Neutrophils ; metabolism ; Rats ; Rats, Sprague-Dawley ; Silicosis ; pathology ; Swine

OBJECTIVEThe development of neonatology and the availability of pulmonary surfactant have been helpful in effective reduction of the mortality of very low birth weight infants at the expense of an increasing number of survivors with bronchopulmonary dysplasia (BPD) caused by lung immaturity. BPD is a common syndrome in newborns, especially in preterm infants, when treated with hyperoxia and mechanical ventilation. Unfortunately, there have been no effective measure for the prevention and treatment of BPD. The purpose of this study was to investigate the influence of recombinant human insulin-like growth factor-1 (rh-IGF-1) on cell apoptosis and Clara cell secretory protein (CCSP) expression during the lung injury induced by hyperoxia, so as to assess its effect on the inflammatory lung injury and its developmental repair.

METHODSEighty full term neonatal Wistar rats under the same condition were divided randomly into four groups on the second day after birth. Group I was air control, group II was exposed to hyperoxia, group III air + rh-IGF-1, and group IV was treated with hyperoxia + rh-IGF-1. The pups in the control group were kept in room air, while pups in hyperoxia group were kept in a Plexiglas chamber and exposed to over 85% oxygen. Pups in group III were under the same raising condition except for exposure to room air and treated with intraperitoneal injection of rh-IGF-1 (1 microg/Kg) everyday from the third day. Pups in group IV were treated with intraperitoneal injection of rh-IGF-1 (1 microg/Kg) everyday from the third day of exposure to hyperoxia. Lung tissue sections of the neonatal rats were stained with hematoxylin and eosin (HE) after 7 d of hyperoxia exposure, expression of CCSP was examined by immunohistochemical method, and apoptotic cell index of lung tissue was calculated by using TUNEL method.

RESULTSIt was observed from immunohistochemical examination that positive staining of CCSP was distributed mainly in distal and respiratory bronchioles. The percentage of Clara cells in distal and respiratory bronchioles epithelium decreased in hyperoxia group (32.17 +/- 3.19)% compared to that in air control group (68.32 +/- 2.04)%, P < 0.01. Statistically significant differences were found in intensity of positiveness of Clara cells between hyperoxia (29.45 +/- 5.56) and air control group (42.37 +/- 3.24), P < 0.01. TUNEL assay showed that most apoptotic cells were alveolar and bronchial epithelial cells. The apoptotic index increased significantly in the hyperoxia group (55.77 +/- 6.09)% compared to the air control group (16.41 +/- 4.01)%, (P < 0.01). The positive rate (52.98 +/- 2.68)% of Clara cells and the expression (41.22 +/- 6.36) of CCSP in hyperoxia + rh-IGF-1 group increased significantly when compared with hyperoxia group, and the differences between these two group were also statistically significant (P < 0.01). The apoptotic index increased significantly in the hyperoxia + rh-IGF-1 group (27.98 +/- 3.09)% compared to the hyperoxia group (P < 0.01).

CONCLUSIONSHyperoxia exposure can promote the pneumocyte apoptosis and inhibit the expression of CCSP. Rh-IGF-1 can remove the block of the formation of lung alveoli, increase the secretion of CCSP, mitigate inflammatory responses in airway and alleviate lung injury via pneumocyte apoptosis. Therefore, the results of this study provide a theoretic and experimental evidence for clinical application of rh-IGF-1 in prevention and treatment of BPD.

Alveolar Epithelial Cells ; metabolism ; Animals ; Apoptosis ; Epithelial Cells ; Humans ; Hyperoxia ; metabolism ; pathology ; Infant, Newborn ; Insulin-Like Growth Factor I ; genetics ; metabolism ; Lung ; Oxygen ; metabolism ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar ; Uteroglobin ; metabolism

OBJECTIVETo identify histopathologic changes of major organs and to correlate clinical symptoms in patients infected by avian influenza H5N1.

METHODSAutopsy study was performed in two patients died of avian influenza HSN1 infection, following conventional protocols and strict safety procedures. Tissue samples from all major organs of two cases and lung samples of one case were collected and fixed in 4% formaldehyde. Histopathologic changes were evaluated by light microscope.

RESULTSDiffuse alveolar damage (DAD) of the lung was seen in both cases. Lesions at various stages of development were seen involving different areas of the lung. At the early stages, the lungs exhibited exudative changes, including capillary congestion, necrosis of alveolar epithelial cells, and intra-alveolar edema. Hyaline membranes were prominent and diffusely distributed along alveoli. In the middle-late stages of the disease, the lungs exhibited proliferative and fibrotic changes, including proliferation of pneumocytes and bronchial epithelium, fibrosis of the interstitium and alveolar spaces. Lung biopsy tissue of one case showed DAD and interstitial fibrosis in a background of bronchiectasis. Lymph nodes and spleens showed quantity reduction of lymphocytes and active hemophagocytosis. Other changes in major organs included interstitial carditis in one case and acute renal tubular necrosis in one case. In one case, the brain showed edema with cytoplasmic eosinophilia, loss of structure, axon welling and focal necrosis around ventricle. Multiple foci of trophoblastic necrosis with dystrophic calcification were observed in placenta of one pregnant patient. Acute necrotizing deciduitis was found focally. Sections of fetal lung showed edema and scattered interstitial neutrophils were consistent with acute interstitial pneumonitis.

CONCLUSIONSThe respiratory tract is the major target of avian influenza A H5N1 virus infection. The changes of DAD in the lungs resulted in hypoxia, leading to multiple organ failure and death.

Adult ; Alveolar Epithelial Cells ; pathology ; Animals ; Birds ; Fatal Outcome ; Female ; Humans ; Influenza A Virus, H5N1 Subtype ; pathogenicity ; Influenza in Birds ; pathology ; physiopathology ; virology ; Influenza, Human ; pathology ; Male ; Pregnancy ; Pulmonary Fibrosis ; etiology ; pathology

OBJECTIVETo investigate the mechanism of methyl tertiary-butyl ether (MTBE)-induced animal carcinoma.

METHODSSingle cell gel electrophoresis assay (SCGE), DNA cross-links test and unscheduled DNA synthesis (UDS) assay were conducted with cultured rat type II pneumocytes and rat hepatocytes in vitro. Except UDS assay, the same experiment was performed in hepatocytes, renal cells and pneumocytes of mice administrated MTBE by inhalation at 0, 108, 1,440 and 4,968 mg/m(3) for 20 consecutive days. Simultaneously, the contents of malondialdehyde (MDA) in homogenates of lung and kidney were determined.

RESULTSThe lengths of DNA migration in mice hepatocytes at 1,440, 4,968 mg/m(3) of MTBE, renal cells at all doses of MTBE, and pneumocytes at 4,968 mg/m(3) were greater than those in negative controls. There was dose-effect relationship between the concentration of MTBE and hepatocytes DNA migration lengths in mice (r = 0.997, P = 0.003). MTBE of 1,440 and 4,968 mg/m(3) contributed to a rise in MDA of renal homogenates in female mice (P < 0.05). MTBE above 0.050 mmol/L caused greater DNA migration in cultured rat type II pneumocytes and rat hepatocytes in vitro (P < 0.05), and also with dose-effect relationship (r(lung) = 0.967, r(liver) = 0.963, P < 0.05)). In UDS assay, DNA synthesis of rat type II pneumocytes and rat hepatocytes were increased at the concentration of 5.0 mmol/L and 10.0 mmol/L of MTBE.

CONCLUSIONMTBE has some genotoxicity on DNA, and the single strand breaks of cell and lipid peroxidation may be one of the possible mechanism of MTBE-induced hepatic and renal tumors of animal.

Alveolar Epithelial Cells ; drug effects ; Animals ; Cells, Cultured ; Comet Assay ; DNA Damage ; drug effects ; Female ; Hepatocytes ; drug effects ; Kidney ; metabolism ; pathology ; Liver ; metabolism ; pathology ; Male ; Methyl Ethers ; toxicity ; Mice ; Rats

OBJECTIVETo investigate the effects of cyclosporine A (CsA), a powerful inhibitor of mitochondrial permeability transition pore (MPTP), on pneumocyte apoptosis, the release of cytochrome C and the activity of caspase-3 after lung ischemia/reperfusion, and explore the mechanisms.

METHODSSingle lung in situ ischemia/reperfusion animal model was used. 30 SD rats were randomly divided into three groups (n = 10): sham (S) group, ischemia/reperfusion (I/R) group and cyclosporine A (CsA) group. Apoptosis of pneumocyte was assessed by TUNEL method, cytochrome C (CytC) in cytoplasm was detected by immunohistochemistry techniques, and the activity of caspase-3 was measured with spectrophotometer.

RESULTSThe content of CytC in cytoplasm, the activity of caspase-3, and the value of apoptosis index (AI) in ischemia/reperfusion group were evidently higher than that in S group (P < 0.01). CsA suppressed apoptosis as well as CytC release and caspase-3 activity (P < 0.01).

CONCLUSIONCsA can prevent the release of cytochrome C, block the apoptosis of pneumocyte accordingly maybe by closing the MPTP.

Alveolar Epithelial Cells ; cytology ; drug effects ; Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cyclosporine ; pharmacology ; Cytochromes c ; metabolism ; Lung ; blood supply ; pathology ; Male ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism ; pathology

OBJECTIVETo investigate the effects of Matrigel on expression of focal adhesion kinase and on proliferation and apoptosis of alveolar epithelial cell II of premature rat exposed to hyperoxia.

METHODSThe primary premature rat AECII (gestation 19 d) were cultured in vitro. For establishing hyperoxia-exposed cell model, purified AECII were cultured for 12 hours after culture flasks were filled with 95% oxygen-5% CO2 at 5 L/min, and then sealed for 12 hours. DNA content, phosphor and total protein of FAK were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blotting respectively after 12 hours of air or hyperoxia exposure in the presence or absence of Matrigel. To investigate the relationship between FAK activated and proliferation or apoptosis of type II alveolar epithelial cells, levels of proliferation and apoptosis of AECII were measured by immunohistochemical assay of proliferating cell nuclear antigen (PCNA) and TUNEL method respectively.

RESULTSFAK and FAK-Tyr(397) activity of AECII on Matrigel-coated substrate increased: compared with air group, the expression of PCNA decreased and apoptotic index increased markedly in hyperoxia group (0.1498 ± 0.009 vs. 0.0953 ± 0.006, P < 0.05; 1.232 ± 0.6 vs. 13.40 ± 3.2, P < 0.01), but the expression of PCNA of AECII on Matrigel-coated substrate increased significantly (0.1498 ± 0.009 vs. 0.1921 ± 0.008, P < 0.01) and apoptotic index did not change. The expression of PCNA increased significantly (0.0953 ± 0.006 vs. 0.1125 ± 0.012, P < 0.05) and apoptotic index decreased markedly in hyperoxia + Matrigel group as compared with hyperoxia group (13.40 ± 3.2 vs. 7.641 ± 1.6, P < 0.05).

CONCLUSIONHyperoxia decreased the level of FAK and FAK-Tyr(397) in AECII, which may be a contributory mechanism of impaired proliferation and apoptosis of AECII in hyperoxia induced lung injury in premature rat. Matrigel could inhibit apoptosis and promote proliferation of AECII resulted from hyperoxia in vitro. Matrigel may play a protective role in hyperoxia-induced lung injury partly due to activated FAK.

Alveolar Epithelial Cells ; Animals ; Animals, Newborn ; Apoptosis ; Cell Proliferation ; Cells, Cultured ; Collagen ; pharmacology ; Drug Combinations ; Epithelial Cells ; drug effects ; enzymology ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Hyperoxia ; Laminin ; pharmacology ; Male ; Proteoglycans ; pharmacology ; Pulmonary Alveoli ; cytology ; enzymology ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate characteristics of pulmonary stem cells labeled with bromodeoxyuridine (Brdu) and telomerase reverse transcriptase (TERT) in lung tissue, as well as the effects of proliferation and differentiation of the stem cells on lung development and repair of pulmonary injury.

METHODSA model of hyperoxia in neonatal rats was made by exposing the rats to 95% O2 for 7 d. Before sacrificing the rats, Brdu was injected through peritoneum, and immune staining positive cells were analyzed after the rats were sacrificed. TERT positive cells were stained by an immunohistochemical method. At the same time, the double staining for surfactant protein C (SPC) and Brdu or SPC and TERT were performed. Lung histologic study was done on HE stained tissue slices.

RESULTS(1) The lung with hyperoxic injury had thinner walls of alveoli, simple alveolar structure, fewer and larger alveoli, expanded and shrunken alveoli, and there were many fell-off alveolar epithelial cells in the alveolar cavities as well. (2) The cells positively stained with Brdu located in septa, mucosa and submucosa of various bronchi, scattering in epithelium of bronchi, and the number of positive cells was low, having a large nucleus. The TERT-positive cells were apparent in the septa and alveolar walls of peripheral lung tissue, characterized by uneven distribution in the lung lobes, the number of positive cells was less than that of Brdu-positive cells [integral of expression (1.61 +/- 0.83) vs. (0.62 +/- 0.55), P < 0.05]. The number of Brdu- and TERT-positive cells had no significant difference in hyperoxic rats compared to that in controls [integral of expression (1.43 +/- 0.85) vs. (1.61 +/- 0.83); (0.62 +/- 0.55) vs. (0.83 +/- 0.84), P > 0.05]. (3) After double staining, a few positive cells were found in double-stained tissues with SPC and Brdu or TERT. (4) The cells positively stained with SPC antibody had different size. The percentage of positive cells was not significantly different between the hyperoxia group (80.3%) and control group (78.6%). The Brdu positive staining located in nucleus of cells that had larger size than the cells not stained, round nucleus with intense staining (seldom, pole-shaped) and the number of such cells was less than that of the SPC positive cells. The percentage of positive cells was not significantly different between the hyperoxia group (28.5%) and control group (21.4%). (5) The TERT staining located in nucleus of cell that had smaller size than the cells not stained, various nuclear shape, including round intensively stained, round slightly stained, pole-shaped and divided shape. The percentage of positive cells was not significantly different between the hyperoxia group (2.3%) and control group (1.5%).

CONCLUSIONS(1) Brdu and TERT, as markers of stem cells having different capability of differentiation, possess special characteristics, respectively. The cells with Brdu could be transit amplifying cell (TAC) which retains characteristics of stem cells originated from differentiated stem cells, while, the cells stained with TERT especially reflects the characteristics of stem cells. (2) The proliferation and differentiation of pulmonary stem cells during hypoxic lung injury are limited and may be related with arrest of alveolization.

Alveolar Epithelial Cells ; pathology ; Animals ; Animals, Newborn ; Biomarkers ; metabolism ; Bromodeoxyuridine ; metabolism ; Cell Differentiation ; Cell Proliferation ; Disease Models, Animal ; Female ; Hyperoxia ; complications ; Immunohistochemistry ; Lung ; cytology ; metabolism ; pathology ; Lung Injury ; etiology ; metabolism ; pathology ; physiopathology ; Male ; Peptides ; metabolism ; Rats ; Rats, Sprague-Dawley ; Stem Cells ; metabolism ; pathology ; Telomerase ; metabolism