OBJECTIVETo explore the differences of the silica-induced inhibition on cellular proliferation and hprt gene mutagenesis between lung fibroblasts and alveolar type II cells.

METHODSThe proliferation inhibitive cytotoxicity was detected by MTT (3-[4,5-Dimethylthiazolzyl]-2,5-Diphenyl Tetrazolium Bromide) colorimetric method. Mutation in the hprt gene was screened by culture in the presence of the toxic purine analog, 6-thioguanine (6-TG).

RESULTSUnder the same circumstances of silica exposure, alveolar type II cells was more sensitive than lung fibroblasts for proliferation inhibition. The median proliferation inhibition concentration (IC50) of silica on epithelial was 140 micrograms/cm2, whereas IC50 of silica on fibroblasts was 282 micrograms/cm2. At the same doses of silica, the hprt gene mutation frequency in type II cells (84.2 x 10(-6))-156.6 x 10(-6) was statistically higher than that in fibroblasts (67.6 x 10(-6)-114.3 x 10(-6), P < 0.05).

CONCLUSIONThere were significant differences of both silica-induced cell proliferation inhibition and hprt gene mutation between rat lung fibroblasts and type II epithelial cells. In vitro, cultured rat alveolar type II cells were more sensitive in cytotoxicity and hprt gene mutagenesis to silica dust than lung fibroblasts were.

Animals ; Cell Proliferation ; drug effects ; Epithelial Cells ; drug effects ; Fibroblasts ; drug effects ; Hypoxanthine Phosphoribosyltransferase ; genetics ; Lung ; cytology ; drug effects ; metabolism ; Mutation ; Pulmonary Alveoli ; cytology ; drug effects ; Rats ; Silicon Dioxide ; toxicity

Pulmonary hypertension (PH) is characterized by structural and functional changes in the lung including proliferation of vascular smooth muscle cells (VSMCs) and excessive collagen synthesis. Although connective tissue growth factor (CTGF) is known to promote cell proliferation, migration, adhesion, and extracellular matrix production in various tissues, studies on the role of CTGF in pulmonary hypertension have been limited. Here, we examined CTGF expression in the lung tissues of male Sprague Dawley rats treated with monocrotaline (MCT, 60 microgram/kg), a pneumotoxic agent known to induce PH in animals. Establishment of PH was verified by the significantly increased right ventricular systolic pressure and right ventricle/left ventricle weight ratio in the MCT-treated rats. Histological examination of the lung revealed profound muscular hypertrophy in the media of pulmonary artery and arterioles in MCT-treated group. Lung parenchyma, vein, and bronchiole did not appear to be affected. RT-PCR analysis of the lung tissue at 5 weeks indicated significantly increased expression of CTGF in the MCT-treated group. In situ hybridization studies also confirmed abundant CTGF mRNA expression in VSMCs of the arteries and arterioles, clustered pneumocytes, and infiltrated macrophages. Interestingly, CTGF mRNA was not detected in VSMCs of vein or bronchiole. In saline-injected control, basal expression of CTGF was seen in bronchial epithelial cells, alveolar lining cells, and endothelial cells. Taken together, our results suggest that CTGF upregulation in arterial VSMC of the lung might be important in the pathogenesis of pulmonary hypertension. Antagonizing the role of CTGF could thus be one of the potential approaches for the treatment of PH.
Animals ; Blood Pressure/drug effects ; Bronchi/cytology/drug effects/metabolism ; Endothelial Cells/cytology/drug effects/metabolism ; Epithelial Cells/cytology/drug effects/metabolism ; Hypertension, Pulmonary/chemically induced/*metabolism ; Immediate-Early Proteins/genetics/*metabolism ; Intercellular Signaling Peptides and Proteins/genetics/*metabolism ; Lung/cytology/drug effects/*metabolism ; Male ; Monocrotaline/*toxicity ; Pulmonary Alveoli/cytology/drug effects/metabolism ; Pulmonary Artery/cytology/drug effects/metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Reverse Transcriptase Polymerase Chain Reaction ; Up-Regulation

In the study, the effects of Panax notoginseng saponins (PNS) on alveolar epithelial to mesenchymal transition (EMT) and extracellular matrix degradation were observed in a type of human alveolar epithelial cell, A549 cells, stimulated by TGF-beta1. Firstly, MTT method was applied to evaluation of cellular proliferation and found that PNS from 12.5 mg x L(-1) to 200 mg x L(-1) dosage could not inhibit significantly cellular proliferation. Then, cells were divided into five groups, normal group, TGF-beta1 group, TGF-beta1 + 50 mg x L(-1) PNS group, TGF-beta1 + 100 mg x L(-1) PNS group and TGF-beta1 + 200 mg x L(-1) PNS group. Normal cells were not stimulatec by TGF-beta1; TGF-beta1 cells were only stimulated by TGF-beta1 and the other cells were stimulated by TGF-beta1 with different doses of PNS, respectively. After stimulation, cells and supernatants were collected for assays. Cellular roundness was applied to quantitative evaluation of morphological change. Immunocytochemistry was applied to examine E-cadherion, a-SMA and FN proteins expression in the cells. Enzyme linked-immunosorbent assay was applied to MMP-9 and TIMP-1 levels. The results showed that EMT of A549 cells was induced by TGF-beta1, showing significant change of roundness, E-cadherion, alpha-SMA and FN (P < 0.05, P < 0.01). Compared to TGF-beta1, PNS significantly inhibited the changes of roundness (P < 0.05), FN and alpha-SMA (P < 0.05, P < 0.01) and not significantly inhibited the change of E-cadherion. Furthermore, MMP-9 levels were significantly increased by TGFbeta1 stimulation (P < 0.05), without significant change of TIMP-1. Compared with TGF-beta1, PNS could significantly increase MMP-9 level (P < 0.05) and decrease TIMP-1 levels (P < 0.05, P < 0.01). In conclusion, PNS could inhibit alveolar epithelial cell EMT induced by TGF-beta1, with increase of extracellular matrix degradation ability, which showed anti-fibrosis of lung ability.
Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Epithelial-Mesenchymal Transition ; drug effects ; Humans ; Matrix Metalloproteinase 9 ; metabolism ; Panax notoginseng ; chemistry ; Pulmonary Alveoli ; cytology ; drug effects ; metabolism ; Saponins ; pharmacology ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo investigate the protective effect of hydrogen against hyperoxia-induced oxidative stress injury in premature rat type II alveolar epithelial cells (AECs).

METHODSThe type II AECs isolated from premature rats were randomly divided into air (21% oxygen) control group, hyperoxia (95% oxygen) control group, air + hydrogen group, and hyperoxia+ hydrogen group. The cells with hydrogen treatment were cultured in the presence of rich hydrogen. After the corresponding exposure for 24 h, the cell morphology was observed microscopically. MTT assay was used to evaluated the cell proliferation ability, and JC-1 fluorescence probe was used to detect the mitochondrial membrane potential (δφ) changes of the type II AECs. The concentration of maleic dialdehyde (MDA) and superoxide dismutase (SOD) activity in the cell supernatant were detected using colorimetric method.

RESULTSNo significant differences were found in cell growth or measurements between air control and air + hydrogen groups. Compared with air control group, the cells exposed to hyperoxia showed significantly suppressed proliferation, reduced mitochondrial membrane potential, increased MDA content, and decreased SOD activity. Intervention with hydrogen resulted in significantly increased cell proliferation and SOD activity and lowered MDA content, and restored the mitochondrial membrane potential in the cells with hyperoxia exposure (P<0.05).

CONCLUSIONHydrogen can significantly reduce hyperoxia-induced oxidative stress injury in premature rat type II AECs, improve the cellular antioxidant capacity, stabilize the mitochondrial membrane potential, and reduce the inhibitory effect of hyperoxia on cell proliferation.

Animals ; Animals, Newborn ; Antioxidants ; metabolism ; Cell Proliferation ; Cells, Cultured ; Epithelial Cells ; drug effects ; Female ; Hydrogen ; pharmacology ; Male ; Malondialdehyde ; metabolism ; Membrane Potential, Mitochondrial ; Oxidative Stress ; drug effects ; Oxygen ; adverse effects ; Pulmonary Alveoli ; cytology ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; metabolism

AIMTo study the influence of VIP on the expression of SP-A and its intracellular signal transduction pathway.

METHODSThe influence of VIP on the expression of SP-A was studied by immunohistochemistry and RT-PCR. The intracellular signal transduction pathway was further investigated by using receptor antagonist, protein kinase inhibitor and antisense oligonucleotides.

RESULTS(1) VIP(10(-8) mol/L) enhanced SP-A protein expression in alveolar type II cells (ATII) and increased the content of SP-A mRNA in lung tissue. (2) VIP receptor antagonist [D-P-C1-Phe (6)-Leu (17)]-VIP (10(-6) mol/L) could suppress the VIP-induced expression of SP-A protein and SP-A mRNA. (3) c-fos antisense oligonucleotides (9 x 10(-6) mol/L) could inhibit the VIP-induced expression of SP-A protein and SP-A mRNA. (4) Protein kinase C(PKC) inhibitor H7 (10(-5) mol/L) could also depress the V1P-induced SP-A protein and SP-A mRNA.

CONCLUSIONVIP can up-regulate the expression of SP-A through its receptor. PKC and c-fos protein play important roles in the intracellular signal transduction pathway through which VIP induces the expression of SP-A.

Animals ; Epithelial Cells ; drug effects ; metabolism ; In Vitro Techniques ; Protein Kinase C ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; Pulmonary Alveoli ; cytology ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Rats ; Rats, Wistar ; Signal Transduction ; Vasoactive Intestinal Peptide ; pharmacology

OBJECTIVETo explore the effect of terbutaline on sodium transport in rat alveolar type I (ATI) and type II (ATII) cells of rats.

METHODSThe whole cell currents were recorded from ATII cells isolated from rat lungs perfused with or without amiloride (inhibitor of epithelial sodium channel) and ZnCl(2) (inhibitor of cyclic nucleotide-gated cation channel) in the whole cell recording mode using the patch-clamp technique. The effect of terbutaline on the currents was examined.

RESULTSThe main currents recorded from ATII cells were amiloride-sensitive and Zn(2+)-sensitive. The amiloride-sensitive and Zn(2+)-sensitive current shared a similar proportion (P>0.05). Both currents could be significantly increased by terbutaline (P<0.05), and the proportion of amiloride-sensitive current was 1.7 times that of Zn(2+)-sensitive current (P<0.05).

CONCLUSIONThere are functional epithelial sodium channels (ENaC) and cyclic nucleotide-gated cation channels (CNG) on freshly isolated ATII cells, both serving as the main channels for sodium transport. Terbutaline increases the absorption of alveolar fluid primarily by increasing sodium transport of ENaC and CNG on ATI and AT II cells.

Amiloride ; pharmacology ; Animals ; Chlorides ; pharmacology ; Cyclic Nucleotide-Gated Cation Channels ; antagonists & inhibitors ; drug effects ; Male ; Peptides ; pharmacology ; Pulmonary Alveoli ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Sodium ; metabolism ; Sodium Channels ; drug effects ; Terbutaline ; pharmacology ; Zinc Compounds ; pharmacology

OBJECTIVE: To explore the effect of hepatocyte growth factor (HGF) on the proliferation, apoptosis and function of hyperoxia exposed Type II alveolar epithelial cells (AEC II) isolated from premature rat lungs, and to explore the mechanism of the protective effect of HGF on hyperoxia-induced lung injury. METHODS: Type II alveolar epithelial cells from fetal rat lungs were cultured. After being purified, AEC II was randomly divided to 4 groups: air group (Air), hyperoxia group (HO), air plus hepatocyte growth factor group (Air+HGF), hyperoxia plus hepatocyte growth factor group (HO+HGF) . The mRNA levels of surfactant associated protein, SPs (including SPA, SPB, SPC) were measured by RT-PCR. The proliferation and apoptosis of AEC II were analyzed with flow cytometric assay and Western blot. RESULTS: (1) Compared with Air group, the apoptosis rate increased significantly in the HO group, while G(2)/M phase percentage and the protein expression levels of proliferating cell nuclear antigen (PCNA) decreased significantly (P<0.01); the S phase percentage and the protein expression levels of PCNA increased significantly in the Air+HGF group. (2) In the HO +HGF group, the apoptosis rate was not significantly different, G0/G1 phase percentage decreased significantly, S phase, G(2)/M phase percentage and the protein expression levels of PCNA increased significantly compared with the HO group. (3) SPs mRNA levels significantly decreased in the HO group compared with those in the Air group. After HGF was added, SPs mRNA levels increased in the HO +HGF group and the Air+HGF group compared with the HO group. CONCLUSION Hyperoxia can inhibit the proliferation, increase the apoptosis rate and decrease SPs mRNAs levels of AEC II in vitro in premature rats, while HGF can partly inhibit the changes of SPs mRNAs levels and cell proliferation of AEC II resulted from hyperoxia, and HGF may play a protective role in hyperoxia-induced lung injury.
Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Epithelial Cells ; drug effects ; metabolism ; Female ; Hepatocyte Growth Factor ; pharmacology ; Hyperoxia ; metabolism ; pathology ; Male ; Pregnancy ; Proliferating Cell Nuclear Antigen ; metabolism ; Pulmonary Alveoli ; cytology ; drug effects ; Pulmonary Surfactant-Associated Proteins ; metabolism ; Rats ; Rats, Sprague-Dawley

This study is to investigate the effect of artesunate on transforming growth factor-beta1 (TGF-beta1) induced epithelial-mesenchymal transition (EMT) and its possible mechanism. After the in vitro cultured RLE-6TN cells were treated with TGF-beta1 then artesunate intervened on it, after 24 h, expression of the markers of mesenchymal cell was assayed using Western blotting and real-time PCR analysis. Western blotting was also used to detect the effect of TGF-beta1 on the Smad3 and Smad7 expressions of RLE-6TN cells. Morphological alterations were examined by phase-contrast microscope, and ultrastructure changes by electron microscope. Incubation of RLE-6TN cells with TGF-beta1 resulted in the up-regulation of the expression of the mesenchymal cell markers, after artesunate intervened on it, resulted in the down-regulation of the expression. Meanwhile, incubation with artesunate intervened on RLE-6TN cells could lead to the apparent down-regulation of the expression of Smad3 and up-regulation of Samd7 and the transition of RLE-6TN cells to mesenchymal-like by TGF-beta1 induction, after artesunate intervened on it, RLE-6TN cells to epithelial-like. TGF-beta1 induced epithelial-mesenchymal transition process; artesunate can inhibit TGF-beta1-induced epithelial-mesenchymal transition process, the possible mechanism is up-regulation of the expression of Smad7 and down-regulation of the expression of Smad3, meanwhile inhibits phosphorylation of Smad3.
Actins ; genetics ; metabolism ; Animals ; Artemisia ; chemistry ; Artemisinins ; isolation & purification ; pharmacology ; Cell Line ; Cell Proliferation ; drug effects ; Epithelial Cells ; cytology ; metabolism ; Epithelial-Mesenchymal Transition ; drug effects ; Idiopathic Pulmonary Fibrosis ; pathology ; Plants, Medicinal ; chemistry ; Pulmonary Alveoli ; cytology ; RNA, Messenger ; metabolism ; Rats ; Smad3 Protein ; genetics ; metabolism ; Smad7 Protein ; genetics ; metabolism ; Transforming Growth Factor beta1 ; pharmacology ; Vimentin ; genetics ; metabolism

The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary culture from 20-days fetal rat lung and hyperoxia-exposed cell model was established. Cell proliferating viability was examined by MTT assay after treatment of amygdalin at various concentrations. DNA content and the proliferating cell nuclear antigen (PCNA) protein expression of AEC2 were measured by using flow cytometry and immunocytochemistry respectively after 24 h of hyperoxia exposure or amygdalin treatment. The results showed that hyperoxia inhibited the proliferation and decreased PCNA protein expression in A-EC2 of premature rat in vitro. Amygdalin at the concentration range of 50-200 micromol/L stimulated the proliferation of AEC2 in a dose-dependent manner, however, 400 micromol/L amygdalin inhibited the proliferation of AEC2. Amygdalin at the concentration of 200 micromol/L played its best role in facilitating proliferation of AEC2s in vitro and could partially ameliorated the changes of proliferation in hyperoxia exposed AEC2 of premature rat. It has been suggested that hyperoxia inhibited the proliferation of AEC2s of premature rat, which may contribute to hyperoxia lung injury. Amygdalin may play partial protective role in hyperoxia-induced lung injury.
Amygdalin ; isolation & purification ; pharmacology ; Animals ; Animals, Newborn ; Cell Hypoxia ; Cell Proliferation ; drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Epithelial Cells ; cytology ; drug effects ; Lung ; cytology ; metabolism ; Proliferating Cell Nuclear Antigen ; biosynthesis ; genetics ; Pulmonary Alveoli ; cytology ; drug effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore dysfunction mechanism of rat alveolar type II (AT-II) injured by bleomycin (BLM).

METHODSSD rats were injected with a single intratracheal dose of bleomycin or control saline. On day 7, 14, and 28 following intratracheal bleomycin or saline instillation, animals were killed under overdose of 1.5% sodium pentobarbital (0.25 ml/100 g, i.p.) and bronchoalveolar lavage fluid (BALF) from the lung was tested for the activity of pulmonary surfactant (PS) by the Whihelmy Film Balance. Several concentrations of bleomycin stimulated the culture of rat AT-II cells, and surfactant protein (SP) A, B, and aquaporin-1 (AQP) mRNA were analyzed by fluorescent quantitative polymerase chain reaction (FQ-PCR).

RESULTSThe activity of PS and hypoxemia significantly decreased on day 7 and improved on day 14 and completely recovered to normal status on day 28. SP-A, B, and AQP-1 mRNA expression in BLM-stimulated group were significantly lower than those in the control group (P<0.001).

CONCLUSIONBLM-injured AT-II cells decrease the levels of SP-A, B, and AQP-1 mRNA and cause PS dysfunction, resulting in hypoxemia and pneumonedema.

Animals ; Aquaporin 1 ; biosynthesis ; genetics ; Bleomycin ; administration & dosage ; toxicity ; Cells, Cultured ; Dose-Response Relationship, Drug ; Epithelial Cells ; drug effects ; metabolism ; Hypoxia ; chemically induced ; metabolism ; pathology ; Male ; Pulmonary Alveoli ; cytology ; drug effects ; Pulmonary Surfactant-Associated Protein A ; biosynthesis ; genetics ; Pulmonary Surfactant-Associated Protein B ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Time Factors