BACKGROUNDBleomycin-induced fibrosis is extensively used to model aspects of the pathogenesis of interstitial pulmonary fibrosis. This study aimed to determine the benefic effects and mechanisms of simvastatin on bleomycin-induced pulmonary fibrosis in mice.

METHODSBleomycin-induced pulmonary fibrosis mice were administered with simvastatin in different doses for 28 days. We measured inflammatory response, fibrogenic cytokines and profibrogenic markers in both bleomycin-stimulated and control lungs, and correlated these parameters with pulmonary fibrosis.

RESULTSSimvastatin attenuated the histopathological change of bleomycin-induced pulmonary fibrosis and prevented the increase of lung hydroxyproline content and collagen (I and III) mRNA expression induced by bleomycin. Moreover, simvastatin down-regulated the increased expression of transforming growth factor-beta1 (TGF-beta1) and connective tissue growth factor (CTGF) induced by bleomycin at both gene and protein levels. Simultaneously, the accumulation of neutrophils and lymphocytes and the increased production of tumor necrosis factor-alpha (TNF-alpha) in bronchial alveolar lavage fluid were inhibited by simvastatin in early inflammatory phase after bleomycin infusion. The higher dose of simvastatin was associated with a more significant reduction in these inflammatory and fibrotic parameters. Furthermore, the inactivation of p38, RhoA and Smad2/3 signaling pathways was observed during simvastatin administration.

CONCLUSIONSSimvastatin attenuated bleomycin-induced pulmonary fibrosis, as indicated by decreases in Ashcroft score and lung collagen accumulation. The inhibitory effect of simvastatin on the progression of pulmonary fibrosis may be demonstrated by reducing inflammatory response and production of TGF-beta1 and CTGF. These findings indicate that simvastatin may be used in the treatment of pulmonary fibrosis.

Animals ; Antibiotics, Antineoplastic ; Bleomycin ; Mice ; Mice, Inbred C57BL ; Pulmonary Fibrosis ; chemically induced ; metabolism ; pathology ; Simvastatin ; pharmacology

OBJECTIVETo Investigate the biological effects of miR-144 in rats' pulmanory injury induced by nanosized SiO₂preliminarily.

METHOD150 healthy SD rats were divided into five groups randomly: the control group, the nanosized SiO₂groups of 6.25, 12.5, 25.0 mg/ml, and the microsized SiO₂group of 25.0 mg/ml, 30 rats each group. Six rats were sacrificed for their pathological change on the 7th, 15th, 30th, 60th and 90th day after exposure. The expression levels of mature miR-144 in lung tissue of the rats after instilled intracheally nanosized SiO₂at 90d was detected by Quantitative Reverse Transcription PCR. Target prediction for miR-144 was conducted by databases of Target-scan, microRNA.org and miRDB. Function-significant enrichment analysis and signal pathway analysis for predicted target genes were respectively conducted by the Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes, then target genes related to pulmonary fibrosis were screened out.

RESULTSThe expression of miR-144 was up-regulated in lung tissue of rats exposed to nanosized SiO₂. The result was consistent with the results of high-throughput sequencing Hiseq 2000. The target genes of miR-144 related to fibrosis or signal pathway involved in fibrosis were screened out.They are SMAD4, SMAD5, ADAMTS3, ADAMTS15 and ADAMTS19.

CONCLUSIONMiR-144 probably participate in the regulation of fibrosis, which may play an important role in pulmonary injury induced by nanosized SiO₂.

Animals ; Lung ; pathology ; Lung Injury ; chemically induced ; metabolism ; pathology ; MicroRNAs ; metabolism ; Nanoparticles ; adverse effects ; Pulmonary Fibrosis ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Silicon Dioxide ; toxicity

AIMTo observe the expression of a-smooth muscle actin(a-SMA) in primary cultural fibroblasts of rats.

METHODS12 female Wistar rats were randomly assigned into two groups, the normal group and the model group. The model group was filled with bleomycin A2 (5 mg/kg) once into the trachea. The normal group was filled with equal saline into the trachea. The rats were sacrificed under drugged state at 28 days of feeding, then Hematoxylin-Eosin staining and electron microscopy were used to evaluate the foundation of the model. The isolated fibroblasts from the rats were cultured in vitro. Flow cytometry was used in the test to observe the expression of alpha-SMA in fibroblast in vitro in rats.

RESULTSThe formation of fibroblast foci was observed in the model group by optical microscope. The ultrastructure in pulmonary tissue of the model group rats were changed and proliferated myofibroblasts with filaments were found in the alveolar septa by electron microscopy. The expression of alpha-SMA was positive in the normal and model group. There was no difference between the two groups in the rates of positive cells (P > 0.05).

CONCLUSIONBoth the normal and model groups had the phenotype conversion in lung fibroblasts in vitro.

Actins ; metabolism ; Animals ; Bleomycin ; Cells, Cultured ; Female ; Fibroblasts ; metabolism ; pathology ; Lung ; pathology ; Myofibroblasts ; pathology ; Pulmonary Fibrosis ; chemically induced ; pathology ; Rats ; Rats, Wistar

OBJECTIVETo determine the effects of curcumin on bleomycin (BLM)-induced pulmonary fibrosis in rats.

METHODOne hundred and forty-four male Sprague-Dawley rats were randomized into 6 groups (24 rats in each group, model group, sham group, prednisone group (0.56 mg x kg(-1) x d(-1)), curcumin with low dose 5 mg group, curcumin with middle dose group 10 mg and curcumin with high dose group 20 mg per 100 g of body weight). Rats in all groups except in sham group were injected with BLM intratracheally. Curcumin with different doses were given by gavage one time everyday for 7, 14 and 28 days. Prednisone were given to rats in prednisone group, po, serving as the positive treatment group. On the 7th, 14th, 28th day, the lung functions (inspiratory resistance, maximal volutary ventilation, forced vital capacity, Fev 0.2/FVC, peak expiratory flow) were determinated in experimental rats, respectively, and the concentrations of hydroxyproline in lung homogenates of each rat were assayed.

RESULTAdministration of curcumin in different doses improved lung functions of BLM-induced fibrotic rats in the all experimental days; and it decreased the concentration of hydroxyproline in lung homogenates compared with those levels in model control group; and it also lessened the hyperplasia of BLM-induced pulmonary fibrosis in rats.

CONCLUSIONAdministration of curcumin can suppress BLM induced pulmonary fibrosis indicated by improved respiratory function, as well as companied with low content of hydroxyproline in lung tissue of rats.

Animals ; Bleomycin ; adverse effects ; Curcumin ; pharmacology ; Hydroxyproline ; metabolism ; Lung ; drug effects ; metabolism ; pathology ; physiopathology ; Male ; Pulmonary Fibrosis ; chemically induced ; metabolism ; pathology ; physiopathology ; Rats ; Time Factors

OBJECTIVETo explore the characteristics of LN and type I, III collagen in pulmonary fibrosis induced by uranium ore dust in rats.

METHODS60 adult Wistar rats were divided randomly into two groups, control group (30 rats) and uranium ore dust group (30 rats). Non-exposed intratracheal instillation method was used. Uranium ore dust group was exposed 20 mg/ml uranium ore dust suspension 1ml per rat, meanwhile control group was exposed normal saline 1ml per rat. Post-exposed the 7, 14, 21, 30 and 60 d, 6 rats in each group were killed randomly, lung tissue were collected. The pathological changes in lung tissue were observed by microscope using HE staining, the collagen I and III in lungs were observed by polarizing microscope using Biebrich scarlet staining. The expression of LN protein in lung tissue was observed by immunohistochemistry-SP.

RESULTSDuring lung fibrosis, a large amount of the proliferated I and III collagen in lungs were observed. Post-exposure to uranium ore dust, the characteristics in proliferated collagen in lungs were type I collagen deposited in lung interstitium mainly in the early stage. The area percentage of collagen I and III was increased significantly at 7, 14, 21, 30 and 60d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). The over expression of LN in the lung tissue were observed. The expression of LN was distributed in the lung tissue as thickening of the linear or cluster. The integral optical density of LN was increased significantly at 21, 30 and 60 d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01).

CONCLUSIONSAfter exposure to uranium ore dust, the characteristics in proliferated collagen in lungs are the type of I collagen deposited in lung interstitium mainly in the early stage, while the type of III collagen increase significantly at the later period. The overexpression of LN exists in the process of pulmonary fibrosis. It suggests that LN has a role effect in the process of pulmonary fibrosis.

Animals ; Collagen Type I ; metabolism ; Collagen Type III ; metabolism ; Dust ; Female ; Laminin ; metabolism ; Male ; Pulmonary Fibrosis ; chemically induced ; metabolism ; pathology ; Rats ; Rats, Wistar ; Uranium ; adverse effects

OBJECTIVETo investigate whether connective tissue growth factor (CGGF) is expressed in mast cells (MCs) in lung in the development of bleomycin (BLM)-induced pulmonary fibrosis.

METHODSThirty-two male SD rats were randomly divided into 2 groups: BLM group and control group (n=16). The rats in BLM group were received single intratracheal instillation of BLM (5 mg/kg), and the rats in control group received equal volume of 0.9% normal saline(NS) to BLM. The rats in each group were sacrificed for lung tissue sampling on day 14 and day 28 after intratracheal instillation respectively. As the index of the severity of pulmonary fibrosis, the content of hydroxyproline in lungs was analyzed by chloramine T method. Mast cells and CTGF expression in lungs were examined by toluidine blue stain and immunohistochemical assay respectively.

RESULTS(1) On day 28 after intratracheal instillation of BLM, the content of hydroxyproline in lungs of rats was higher than that of control rats (P < 0.01). (2) Compared to control rats, the rats on day 14 and day 28 after instillation of BLM showed increased number of mast cells (Both P < 0.01) and up-regulated CTGF expression (Both P < 0.01). (3) No CTGF immuno-positive MCs were seen in the lungs of control rats whereas CTGF immuno-positive MCs were observed in the pathological areas in lungs of rats on day 14 and day 28 after BLM.

CONCLUSIONCTGF is expressed in MCs in lungs in the development of pulmonary fibrosis, which might be one of the mechanisms underling promoting effect of MCs on fibrosis in lung.

Animals ; Bleomycin ; Connective Tissue Growth Factor ; metabolism ; Lung ; metabolism ; pathology ; Male ; Mast Cells ; metabolism ; Pulmonary Fibrosis ; chemically induced ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the pulmonary toxicity of different concentrations of nano-silica (nano-SiO2) under continuous dynamic inhalation conditions in the rat.

METHODS48 male Sprague-Dawley rats were randomly divided into four groups, including the dispersant control group (saline) and nano-SiO2 low-dose group (0.3%, w/v), the middle-dose group (1%) and the high-dose group (3%). Animals were sacrificed at 28 d after exposure under continuous dynamic inhalation conditions, and bronchoalveolar lavage fluid (BALF) and lung tissue were collected. And following items were observed: body coefficient, BALF related items (leukocytes and classification, total protein content, LDH activity), lung tissue pathological changes (HE staining), and pulmonary fibrosis forming (collagen fiber VG staining).

RESULTSCompared to the dispersant control group, there was no significant change on lung organ coefficient in Nano-SiO2 group (P < 0.05). The BALF total WBC count in 1% and 3% in nano-SiO2 groups showed higher value than the dispersant control group (P < 0.05). No obvious changes were found on total protein content and LDH activity in nano-SiO2 groups compared to the dispersant control group (P > 0.05). For differential WBC counts, lymphocyte count in BALF in nano-SiO2 groups was significantly decreased (P < 0.05), monocyte and macrophage counts were significantly increased (P < 0.05), but there was no difference on the proportion of neutrophils (P > 0.05). HE staining results showed that the obvious thickening of alveolar wall in nano-SiO2 groups, inflammatory cell infiltration also increased around the bronchial and vascular wall. Lung fibrosis VG staining showed no significant change of collagen fiber distribution.

CONCLUSIONUnder our experimental conditions, the continuous dynamic inhalation of nano-SiO2 only caused the significant inflammation in rat lungs, pulmonary fibrosis phenomenon could not be observed significantly.

Animals ; Bronchoalveolar Lavage Fluid ; chemistry ; Inhalation Exposure ; Lung ; drug effects ; metabolism ; pathology ; Male ; Pulmonary Fibrosis ; chemically induced ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Silicon Dioxide ; administration & dosage ; toxicity

OBJECTIVETo explore the role of hypoxia-inducible factor 1alpha (HIF-1α) in early lung fibrosis of rats with acute paraquat (PQ) poisoning.

METHODSForty eight healthy SD rats were randomly divided into control group (6 rats) and paraquat poisoning group (42 rats). Control group was exposed to 1 ml normal solution by gastric gavage. The paraquat group was exposed to 1 ml paraquat solution (50 mg/kg) by gastric gavage for 2, 6, 12, 48, 72 and 120 h, respectively. The arterial blood gas analysis (PaO(2)) was detected. The pathological examinations of lung tissues were performed by HE and Mason staining. HIF-1α in lung tissues were measured by immunofluorescence. Western blot assay was used to detect the expression levels of HIF-1α protein in lung tissues.

RESULTSPaO2 of rats exposed to paraquat for 72 h was (62.33 ± 0.22) mm Hg, which was significantly lower than that (96.00 ± 5.20) of control group (P < 0.05). Pathological examination by HE staining indicated that the acute diffuse lesion appeared in the alveolar capillary endothelium, epithelia and interstitial tissues, and there was the inflammatory cell infiltration in the alveolar of rats exposed to paraquat at 2 h after exposure. At 12 h after exposure, the interstitial edema in lung tissues of rats decreased and the alveolar space became narrow. At 120 h after exposure, there were the alveolar structure derangement, abundant cicatrix, more fibroblasts and peripheral inflammation absorption. Pathological examination by Masson staining showed that there was obvious collagen deposition in the alveolar epithelia at 2h after exposure, the increased collagen fibrosis at 24 and 48 h after exposure and the obvious damage of alveolar tissues or much more fibrous connective tissue deposition at 120 h after exposure. The results of western blot and immunofluorescence assays exhibited that the expression levels of HIF-1α in lung tissues at 2, 24 and 48 h after exposure significantly increased, as compared with control group (P < 0.05), but there were no significant differences of HIF-1α expression among sub-groups at different time points after exposure.

CONCLUSIONThe results of present study shown that there were the pulmonary fibrosis and increased expression of HIF-1α in acute PQ poisoning rats at the early stage, and HIF-1α may be associated with pulmonary fibrosis.

Acute Lung Injury ; chemically induced ; complications ; metabolism ; Animals ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Male ; Paraquat ; poisoning ; Pulmonary Fibrosis ; etiology ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVEto observe the expression of the connective tissue growth (CTGF) and a smooth muscle actin (α-SMA) in acute paraquat (PQ) poisoned rats and investigate the mechanism of paraquat-induced pulmonary fibrosis.

METHODSsprague-Dawley rats were randomly divided into two experimental groups: control group (6 rats) and PQ group (56 rats). On the 3rd, the 7th, the 14th, the 28th and the 56th day after exposure, the expression of CTGF and α-SMA were evaluated by SABC Immunohistochemistry and Western blot; and the relationship of the expression with pathologic score, hydroxyproline were also analyzed, respectively. The lung pathological changes of rats were observed and pathological evaluation was made.

RESULTSit was similar that the expression pattern of CTGF, α-SMA detected by immunohistochemistry and Western blot. With the time passing, their expression in PQ group increased gradually compared with control group (P < 0.05 or P < 0.01). The increasing extent of CTGF, α-SMA were gentle on the 3rd, the 7th day. While their increasing extent was rapid from the 14th to the 56th day. CTGF was positively correlated with α-SMA, pathologic score and hydroxyproline respectively (r = 0.74, r = 0.87, r = 0.71, P < 0.05 or P < 0.01). Meanwhile, the histological changes such as lung fibroblast proliferation, disorganized collagen fibers were observed in PQ group.

CONCLUSIONCTGF and α-SMA could play an important role in the development of pulmonary fibrosis caused by paraquat poisoning; CTGF may promote the transformation of fibroblasts to myofibroblasts and further strengthen the ability of synthesis collagen and extracellular matrix.

Actins ; metabolism ; Animals ; Connective Tissue Growth Factor ; metabolism ; Male ; Paraquat ; toxicity ; Pulmonary Fibrosis ; chemically induced ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the dynamic expression of Heat shock protein 70 (Hsp70) in the lungs and plasma of rats with pulmonary fibrosis induced by silicon dioxide (SiO2).

METHODSForty-eight Wistar rats were randomly divided into the control group exposed to normal solution and group exposed to SiO2 (50 mg/ml) with intratracheal injection. Each group was divided into four subgroups. The animals of SiO2 group and control group were sacrificed and lungs were collected on the 7th, 14th and 28th days after exposure, respectively. The left lung tissues were examined with the histopathologic HE staining. The expression and localization of Hsp70 protein in the lung tissues were examined with western blot assay and immunohistochemistry, respectively. The expression levels of Hsp70 protein in the plasma were measured by ELISA.

RESULTSThe expression of Hsp70 in lung tissues of SiO2 group increased on the 7th day and reached the peak value on the 14th day then decreased, but still was significantly higher than that of the control group, the expression of Hsp70 in plasma of SiO2 group still was significantly higher than that of the control group (P < 0.05). The maximum expression level of Hsp70 in plasma of SiO2 group on the 21st day after exposure was 0.216 ± 0.027 µg/ml.

CONCLUSIONThe expression levels of Hsp70 protein in the lung tissues and plasma of the group exposed to SiO2 significantly increased, which were associated with the process of pulmonary fibrosis. It was suggested that Hsp70 protein may play an important biological role in the pulmonary fibrosis induced by SiO2.

Animals ; HSP70 Heat-Shock Proteins ; blood ; metabolism ; Lung ; metabolism ; pathology ; Male ; Pulmonary Fibrosis ; chemically induced ; metabolism ; Rats ; Rats, Wistar ; Silicon Dioxide ; toxicity