Dasatinib attenuated bleomycin-induced pulmonary fibrosis in mice

Abstract

Anti-fibrotic effect of dasatinib, a platelet-derived growth factor receptor (PDGFR) and Src-kinase inhibitor, was tested on pulmonary fibrosis (PF). Adult mice were divided into four groups: mice dissected 21?d after the bleomycin (BLM) instillation (0.08?mg/kg in 200?µl) (I) and their controls (II), and mice treated with dasatinib (8?mg/kg in 100?µl, gavage) for one week 14?d after BLM instillation and dissected 21?d after instillation (III) and their controls (IV). The fibrosis score and the levels of fibrotic markers were analyzed in lungs. BLM treatment-induced cell proliferation and increased the levels of collagen-1, alpha smooth muscle actin, phospho (p)-PDGFR-alpha, p-Src, p-extracellular signal-regulated kinases1/2 and p-cytoplasmic-Abelson-kinase (c-Abl) in lungs, and down-regulated PTEN expression. Dasatinib reversed these alterations in the fibrotic lung. Dasatinib limited myofibroblast activation and collagen-1 accumulation by the inhibition of PDGFR-alpha, and Src and c-Abl activations. In conclusion, dasatinib may be a novel tyrosine and Src-kinase inhibitor for PF regression in mice.     

Mice lacking neutrophil elastase are resistant to bleomycin-induced pulmonary fibrosis

Neutrophil elastase is a serine protease stored in the azurophilic granules of leukocytes. It has been implicated in the pathology of several lung diseases and is generally presumed to contribute to the tissue destruction and extracellular matrix damage associated with these conditions. To delineate the role of neutrophil elastase in pulmonary inflammation and fibrosis, neutrophil elastase-null mice were intratracheally instilled with bleomycin. In neutrophil elastase-null mice, biochemical and morphological characteristics of pulmonary fibrosis were attenuated for at least 60 days after bleomycin administration despite a typical response to bleomycin as evidenced by assessment of indices of DNA and cell damage. Neutrophil burden of bleomycin-treated wild-type and neutrophil elastase-null mice was comparable, and marked neutrophilic alveolitis was manifest in bleomycin-treated neutrophil elastase-null mice. An absence of immunostaining for active transforming growth factor (TGF)-beta in lung tissue from bleomycin-treated neutrophil elastase-null mice suggested a defect in TGF-beta activation, which was confirmed by biochemical assessment of TGF-beta levels in bronchoalveolar lavage fluid and lung tissue. These data point to novel and unexpected fibrogenic consequences of neutrophil elastase activity in the inflamed lung.     

Increased expression of epimorphin in bleomycin-induced pulmonary fibrosis in mice

Epimorphin was originally identified as a mesenchymal, cell surface-associated protein that modulates epithelial morphogenesis in embryonic organs, whereas pulmonary fibrosis is a process of wound healing, which in part mimics the process of fetal lung development. We investigated the temporal and spatial changes in the distribution of epimorphin protein and expression of its messenger RNA (mRNA) in bleomycin-induced pulmonary fibrosis in mice. Immunohistochemical analysis showed that low levels of epimorphin were present in the bronchiolar, alveolar, and vascular walls of normal adult lungs. However, from Day 7 until Day 28 after bleomycin treatment, increasing levels of epimorphin immunoreactivity were detected in the mesenchymal cells and in the extracellular matrix within intra-alveolar fibrotic lesions. Moreover, Northern blots showed corresponding increases in epimorphin mRNA expression. Re-epithelialization of epimorphin-rich intra-alveolar fibrosis was complete by Day 28 after bleomycin, and by Day 56, epimorphin immunoreactivity had declined. In situ hybridization and confocal microscopic studies confirmed expression of epimorphin mRNA by mesenchymal cells situated within early fibrotic lesions, whereas immunoelectron microscopy localized the epimorphin to the endoplasmic reticulum of the mesenchymal cells and to the basement membrane and collagen fibrils in the area. These results suggest that epimorphin may contribute to the remodeling of pulmonary fibrosis via epithelial-mesenchymal interactions.     

Human placental mesenchymal stem cells of fetal origins-alleviated inflammation and fibrosis by attenuating MyD88 signaling in bleomycin-induced pulmonary fibrosis mice

Pulmonary fibrosis is a progressive lung disease that its pathogenic mechanism currently is incompletely understood. Toll-like receptor (TLR) signaling has recently been identified as a regulator of inflammation and pulmonary fibrosis. In addition, mesenchymal stem cells (MSCs) of different origins offer a great promise in treatment of idiopathic pulmonary fibrosis (IPF). However mechanisms of pathogenic roles of TLR signaling and therapeutic effects of MSCs in the IPF remain elusive. In present study, the involvement of TLR signaling and the therapeutic role of MSCs were interrogated in MyD88-deficient mice using human placental MSCs of fetal origins (hfPMSCs). The results showed an alleviated pulmonary inflammation and fibrosis in myeloid differentiation primary response gene 88 (MyD88)-deficient mice treated with bleomycin (BLM), accompanied with a reduced TGF-β signaling and production of pro-fibrotic cytokines, including TNF-α, IL-1β. An exposure of HLF1 lung fibroblasts, A549 epithelial cells and RAW264.7 macrophages to BLM led an increased expression of key components of MyD88 and TGF-β signaling cascades. Of interest, enforced expression and inhibition of MyD88 protein resulted in an enhanced and a reduced TGF-β signaling in above cells in the presence of BLM, respectively. However, the addition of TGF-β1 showed a marginally inhibitory effect on MyD88 signaling in these cells in the absence of BLM. Importantly, the administration of hfPMSCs could significantly attenuate BLM-induced pulmonary fibrosis in mice, along with a reduced hydroxyproline (HYP) deposition, MyD88 and TGF-β signaling activation, and production of pro-fibrotic cytokines. These results may suggest an importance of MyD88/TGF-β signaling axis in the tissue homeostasis and functional integrity of lung in response to injury, which may offer a novel target for treatment of pulmonary fibrosis.     

Role of the chemokine receptor CXCR2 in bleomycin-induced pulmonary inflammation and fibrosis

Pulmonary fibrosis is characterized by chronic inflammation and excessive collagen deposition. Neutrophils are thought to be involved in the pathogenesis of lung fibrosis. We hypothesized that CXCR2-mediated neutrophil recruitment is essential for the cascade of events leading to bleomycin-induced pulmonary fibrosis. CXCL1/KC was detected as early as 6 hours after bleomycin instillation and returned to basal levels after Day 8. Neutrophils were detected in bronchoalveolar lavage and interstitium from 12 hours and peaked at Day 8 after instillation. Treatment with the CXCR2 receptor antagonist, DF2162, reduced airway neutrophil transmigration but led to an increase of neutrophils in lung parenchyma. There was a significant reduction in IL-13, IL-10, CCL5/RANTES, and active transforming growth factor (TGF)-beta(1) levels, but not on IFN-gamma and total TGF-beta(1,) and enhanced granulocyte macrophage-colony-stimulating factor production in DF2162-treated animals. Notably, treatment with the CXCR2 antagonist led to an improvement of the lung pathology and reduced collagen deposition. Using a therapeutic schedule, DF2162 administered from Days 8 to 16 after bleomycin reduced pulmonary fibrosis and levels of active TGF-beta(1) and IL-13. DF2162 treatment reduced bleomycin-induced expression of von Willebrand Factor, a marker of angiogenesis, in the lung. In vitro, DF2162 reduced the angiogenic activity of IL-8 on human umbilical vein endothelial cells. In conclusion, we show that CXCR2 plays an important role in mediating fibrosis after bleomycin instillation. The compound blocks angiogenesis and the production of pro-angiogenic cytokines, and decreases IL-8-induced endothelial cell activation. An effect on neutrophils does not appear to account for the major effects of the blockade of CXCR2 in the system.     

黄芪通过抗氧化抑制博莱霉素诱导的小鼠肺纤维化

目的:研究黄芪对博莱霉素诱导的肺纤维化小鼠氧化/抗氧化水平的影响,探讨黄芪抗纤维化的可能机制。方法:将36只SPF级雌性昆明小鼠随机分为对照组(生理盐水气管内雾化)、博莱霉素组(博莱霉素3mg/kg气管内雾化)和黄芪治疗组(博莱霉素3 mg/kg气管内雾化后黄芪注射液1.7 g·kg~(-1)·d~(-1)腹腔内注射),实验第14天收集小鼠肺组织及血清标本,取小鼠肺组织行HE和Masson染色;RT-PCR法测小鼠肺组织超氧化物歧化酶(SOD)1/2/3、过氧化氢酶(CAT)、NADPH氧化酶2/4(NOX2/4)和α-平滑肌肌动蛋白(α-SMA)的mRNA水平;Western blot法测α-SMA和NOX2/4蛋白表达水平;比色法检测血清丙二醛(MDA)和总抗氧化能力(T-AOC)。结果:博莱霉素组小鼠肺组织病理损伤较正常组明显加重,α-SMA mRNA和蛋白表达,MDA/T-AOC,NOX2、NOX4和SOD3 mRNA表达,以及NOX2蛋白表达较正常组显著上升,黄芪治疗组则显著逆转上述改变;博莱霉素组小鼠NOX4蛋白表达较正常组显著下降,而黄芪治疗组较博莱霉素组显著上升;博莱霉素组和黄芪治疗组小鼠SOD1和CAT mRNA表达均较正常组显著下降;SOD2 mRNA在3个组中表达的差异无统计学显著性。结论:黄芪能够减缓博来霉素诱导的肺纤维化形成,其机制可能与调节氧化/抗氧化平衡有关。     

The calpain inhibitor calpeptin prevents bleomycin-induced pulmonary fibrosis in mice

Pulmonary fibrosis is characterized by progressive worsening of pulmonary function leading to a high incidence of death. Currently, however, there has been little progress in therapeutic strategies for pulmonary fibrosis. There have been several reports on cytokines being associated with lung fibrosis, including interleukin (IL)‐6 and transforming growth factor (TGF)‐β1. We reported recently that two substances (ATRA and thalidomide) have preventive effects on pulmonary fibrosis by inhibiting IL‐6‐dependent proliferation and TGF‐β1‐dependent transdifferentiation of lung fibroblasts. Rheumatoid arthritis is a chronic autoimmune disorder, and its pathogenesis is also characterized by an association with several cytokines. It has been reported that calpain, a calcium‐dependent intracellular cysteine protease, plays an important role in the progression of rheumatoid arthritis. In this study, we examined the preventive effect of Calpeptin, a calpain inhibitor, on bleomycin‐induced pulmonary fibrosis. We performed histological examinations and quantitative measurements of IL‐6, TGF‐β1, collagen type Iα1 and angiopoietin‐1 in bleomycin‐treated mouse lung tissues with or without the administration of Calpeptin. Calpeptin histologically ameliorated bleomycin‐induced pulmonary fibrosis in mice. Calpeptin decreased the expression of IL‐6, TGF‐β1, angiopoietin‐1 and collagen type Iα1 mRNA in mouse lung tissues. In vitro studies disclosed that Calpeptin reduced (i) production of IL‐6, TGF‐β1, angiopoietin‐1 and collagen synthesis from lung fibroblasts; and (ii) both IL‐6‐dependent proliferation and angiopoietin‐1‐dependent migration of the cells, which could be the mechanism underlying the preventive effect of Calpeptin on pulmonary fibrosis. These data suggest the clinical use of Calpeptin for the prevention of pulmonary fibrosis.     

Gender-based differences in bleomycin-induced pulmonary fibrosis

The role of gender and sex hormones is unclear in host response to lung injury, inflammation, and fibrosis. To examine gender influence on pulmonary fibrosis, male and female rats were given endotracheal injections of either saline or bleomycin. Female rats showed higher mortality rates and more severe fibrosis than did male rats, as indicated by higher levels of lung collagen deposition and fibrogenic cytokine expression. To clarify the potential role of female sex hormones in lung fibrosis, female rats were ovariectomized and treated with either estradiol or vehicle plus endotracheal injections of either saline or bleomycin. The results showed diminished fibrosis in the ovariectomized, bleomycin-treated rats without hormone replacement. Estradiol replacement restored the fibrotic response to that of the intact female mice in terms of lung collagen deposition and cytokine expression, which was accompanied by higher plasma estradiol levels. Furthermore, fibroblasts from bleomycin-treated rats exhibited increased responsiveness to estradiol treatment, causing dose-dependent increases in procollagen 1 and transforming growth factor-beta1 mRNA expression relative to untreated controls. Taken together these findings suggest that female mice may have an exaggerated response to lung injury relative to male mice because of female sex hormones, which have direct fibrogenic activity on lung fibroblasts. This may provide a mechanism for a hormonally mediated intensification of pulmonary fibrosis.     

Expression of FACIT collagens XII and XIV during bleomycin-induced pulmonary fibrosis in mice

Collagens XII and XIV are members of a subfamily of fibril-associated collagens with interrupted triple-helices (FACITs) that facilitate the interactions of adjacent collagen fibrils. Using immunohistochemistry and in situ hybridization, we analyzed the spatial and temporal expression pattern of collagens XII and XIV during bleomycin-induced pulmonary fibrosis. C57Bl mice were treated with bleomycin (1 U, i.p., every other day for 8 days) or saline (control), and lung tissue samples were analyzed 2-12 weeks later. Collagen I protein expression was increased in the lung 2 weeks post bleomycin treatment and persisted for at least 12 weeks. In contrast, collagen XII and XIV expression was low until 4 weeks after bleomycin treatment. Whereas collagen XII expression was greatest between 4 weeks and 8 weeks, expression of collagen XIV persisted from 4 to 12 weeks, which suggests that these two proteins may play distinct roles in the fibrotic process. The mRNA for lysyl oxidase (LOX), an enzyme for cross-linking of collagens, had a delayed increase in the lung after bleomycin administration. It reached a maximum after 8 weeks, and persisted throughout the 12 weeks of the study. These data support the hypothesis that fibrosis is a multistep process that involves both collagen accumulation and changes in the molecules that modulate the biomechanical properties of fibrils.     

Didecyldimethylammonium chloride induces pulmonary inflammation and fibrosis in mice

Didecyldimethylammonium chloride (DDAC) is used worldwide as a germicide, in antiseptics, and as a wood preservative, and can cause adverse pulmonary disease in humans. However, the pulmonary toxicity of DDAC has not yet been thoroughly investigated. Mice were intratracheally instilled with DDAC to the lung and the bronchoalveolar lavage (BAL) fluid and lung tissues were collected to assess dose- and time-related pulmonary injury. Exposure to 1500 μg/kg of DDAC caused severe morbidity with pulmonary congestive oedema. When the BAL fluid from survivors was examined on day 3 after treatment, exposure to 150 μg/kg of DDAC caused weakly induced inflammation, and exposure to 15 μg/kg did not cause any visible effects. Next, we observed pulmonary changes that occurred up to day 20 after 150 μg/kg of DDAC exposure. Pulmonary inflammation peaked on day 7 and was confirmed by expression of interleukin-6, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP)-1α, MIP-1β, and regulated upon activation, normal T-cell expressed and secreted in the BAL fluid; these changes were accompanied by altered gene expression of their chemokine (C–C motif) receptor (Ccr) 1, Ccr2, Ccr3, and Ccr5. Cytotoxicity evoked by DDAC was related to the inflammatory changes and was confirmed by an in vitro study using isolated mouse lung fibroblasts. The inflammatory phase was accompanied or followed by pulmonary remodeling, i.e., fibrosis, which was evident in the mRNA expression of type I procollagen. These results suggest that administering DDAC by intratracheal instillation causes pulmonary injury in mice, and occupational exposure to DDAC might be a potential hazard to human health.     

FTS reduces bleomycin-induced cytokine and chemokine production and inhibits pulmonary fibrosis in mice

Bleomycin (BLM), an antitumour drug, is known to cause interstitial pneumonia followed by pulmonary fibrosis, and has often been used to produce an animal model of pulmonary fibrosis. In the present study, we examined the effect of a nonapeptide thymic hormone, facteur thymique serique (FTS), on the murine lung fibrosis induced by intratracheal instillation of BLM. Treatment with FTS ameliorated BLM-induced fibrotic changes in a dose-dependent manner, as indicated by the reduced accumulation of hydroxyproline (HP). In addition, FTS suppressed BLM-induced cellular inflammatory response in the lungs, as evidenced by inhibition of increased lung weight, reduced accumulation of inflammatory leucocytes, including lymphocytes and neutrophils, but not macrophages, and less pronounced histopathological changes. Finally, BLM challenge increased the local synthesis of proinflammatory cytokines, TNF-alpha and IL-1beta and chemokines, MCP-1, MIP-1alpha RANTES, MIP-2 and KC, while administration of FTS suppressed the production of these cytokines, except for MCP-1. These effects of FTS were observed only when mice received intratracheal instillation with BLM. Considered collectively, our results indicated that FTS treatment ameliorated the cellular inflammatory responses and fibrotic changes in the lungs caused by BLM and such inhibition was well correlated with reduced synthesis of several fibrosis-related cytokines, and suggested that FTS may be potentially useful for the treatment of pulmonary fibrosis.     

Inhibition of glutamine transporter ASCT2 mitigates bleomycin-induced pulmonary fibrosis in mice

BackgroundIdiopathic pulmonary fibrosis (IPF) represents a fatal pulmonary disease. Its mechanisms remain unclear and effective therapies are urgently needed. Glutaminolysis is involved in IPF pathology, but little is known about the role of ASCT2 responsible for cellular uptake of glutamine in IPF. We investigated the role of ASCT2 and its therapeutic implication in IPF through knockdown of ASCT2 in mice.MethodsMouse IPF model was established through a single intratracheal administration of bleomycin, and lentivirus-coated ASCT2 siRNA was administrated into mice via caudal vein for knockdown of ASCT2. Mouse blood and lung tissues were collected for biochemical, histological, and molecular examinations.ResultsASCT2 siRNA significantly lowered ASCT2 expression in mouse lung tissues. Knockdown of ASCT2 reduced pulmonary levels of glutamic acid, α-ketoglutarate, glutathione and ATP, mitigated pulmonary histological injury, and reduced serum concentrations of pulmonary injury parameters including SP-A, SP-D, KL-6 and CCL18 in IPF mice. Moreover, serum levels of fibrotic parameters HA, LN, PC-III and IV-C were lowered by ASCT2 depletion. Collagen production and pulmonary hydroxyproline levels were also decreased by ASCT2 siRNA in IPF mice, which was concomitant with downregulation of α-smooth muscle actin, collagen type Iα1 and transforming growth factor-β receptor II. Furthermore, ASCT2 deficiency downregulated the mRNA and protein expression of inflammatory cytokines IL-1β and TNF-α as well as macrophage marker F4/80 in lung tissues of IPF mice.ConclusionsInhibition of ASCT2 effectively mitigated pulmonary injury, fibrosis and inflammation in mice with bleomycin-induced IPF. ASCT2 could be a novel therapeutic target for treatment of IPF.     

Receptor-activated Smad localisation in bleomycin-induced pulmonary fibrosis

BACKGROUND: Recent advances in fibrosis biology have identified transforming growth factor (TGF)-beta type I receptor-mediated activation of Smads as playing a central part in the development of fibrosis. However, to date, there have been few studies that examined the localisation and distribution of receptor-activated Smads protein (R-Smads: Smad2 and 3) during the fibrosis progression. AIMS: To histopathologically assess the time-course change of the localisation and distribution of the Smads protein in pulmonary fibrosis. METHODS: Pulmonary fibrosis was induced by intranasal injection of bleomycin (0.3 U/mouse). Lungs were isolated 2, 5, 7, 9 and 14 days after bleomycin treatment. Histological changes in the lungs were evaluated by haematoxylin-eosin stain or Masson's trichrome stain, and scored. TGF-beta1, Smad3 and phosphorylated Smad2 localisations in lung tissues were determined by immunohistochemistry. RESULTS: The bleomycin treatment led to considerable pulmonary fibrotic changes accompanied by marked increase in TGF-beta1 expression in infiltrating macrophages. With the progression in fibrosis (day 7-14), marked increases in Smad3-positive and pSmad2-positive cells were observed. There were intense Smad3-positive and pSmad2-positive signals localised to the nuclei of the infiltrating macrophages and to type II epithelial cells, and less intense signals in fibroblasts and hyperplastic alveolar/bronchiolar epithelial cells. CONCLUSIONS: The time-course data of TGF-beta1 and R-Smads indicate that progressive enhancement of TGF-beta1 signalling via R-Smad is activated in the process of fibrosis progression.     

Capillary remodeling in bleomycin-induced pulmonary fibrosis.

Lung fibrosis is a process in which collagen is laid down and the delicate capillary-alveolar relationship is disturbed. The architectural changes which occur in the capillaries, a main element of the oxygen transferring unit, are difficult to illustrate without a three-dimensional tool, such as scanning electron microscopy. Therefore, a scanning electron microscopic study was undertaken to show the capillary changes of lung fibrosis. Fibrosis was induced in rats by intratracheal instillation of bleomycin. After 30 days the rats were sacrificed, and the vascular tree of the lung was cast with methacrylate. The fibrosis was patchy. The intercapillary space became wider; and some capillaries had large, irregular dilatations. Occasionally giant capillaries (up to 19 mu in diameter) were noted. The pleural and alveolar capillary diameters increased (P less than 0.01), and the branching frequency decreased (P = 0.02). The center of the capillary rings, which has been suggested to be the site of contractile interstitial cells, increased in size (P = 0.03). The appearance of irregularly shaped capillaries and an increase in diameter without a change in density of alveolar capillaries, resulting in a loss of surface area and a decrease in branching, are the main scanning electron microscopic findings of the remodeling which occurs in pulmonary capillaries in lung fibrosis. These changes may partially explain the functional derangement of this disease.     

丙戊酸钠减轻博莱霉素致大鼠肺纤维化

目的:探讨丙戊酸钠在博莱霉素诱导的肺纤维化中的作用及机制。方法:42只大鼠随机分为正常对照组、模型组和治疗组。造模采用博来霉素5 mg/kg气管内注射,自造模14 d开始分别采用生理盐水(0.5m L/d)、丙戊酸钠(300 mg·kg-1·d-1)和地塞米松(0.6 mg·kg-1·d-1)腹腔内注射治疗14 d。模型组分别在造模后14和、28 d处死。治疗组在造模后28 d处死。然后通过HE染色、Masson染色、羟脯氨酸(HYP)检测和Western blotting检测α-平滑肌肌动蛋白(α-SMA)及E-钙黏蛋白(E-cadherin)表达的变化,综合分析丙戊酸钠对肺纤维化发展的干预作用。结果:HE染色显示丙戊酸钠治疗组的肺泡结构、肺间质的形态优于生理盐水组和地塞米松治疗组。Masson染色及HYP检测用于衡量肺组织内胶原的分布及含量,可见丙戊酸钠治疗组肺组织内胶原的分布及含量均显著低于地塞米松治疗组及生理盐水组。丙戊酸钠可以降低α-SMA的表达,同时上调上皮标志性蛋白E-cadherin的表达。结论:丙戊酸钠可以通过减少胶原的表达与分布及下调间充质蛋白α-SMA,同时上调上皮蛋白E-cadherin的表达从而减轻博来霉素诱导大鼠肺纤维化。     

Inhibition of bleomycin-induced pulmonary fibrosis in mice by the matrix metalloproteinase inhibitor batimastat

Bleomycin-induced pulmonary fibrosis is known to be associated with the increased activity of two gelatinases, matrix metalloproteinase (MMP)-2 and MMP-9, in bronchoalveolar lavage (BAL). This study has investigated the effect of a synthetic inhibitor of MMP, batimastat, on the development of pulmonary fibrosis induced by bleomycin administration in mice. Animals were intranasally instilled with saline or bleomycin (0.5 mg in 100 microl per mouse). Batimastat (30 mg/kg) or vehicle alone was administered by intraperitoneal injection 24 h and 1 h before saline or bleomycin instillation, and then daily at the same dosage until the end of the study. Fifteen days after bleomycin administration, BAL was performed and the lung was removed. Treatment of mice with batimastat significantly reduced bleomycin-induced lung fibrosis, as shown in the lung by histopathological examination and by a decrease in hydroxyproline levels. Batimastat also prevented the increase in BAL macrophage and lymphocyte numbers, whereas it did not show any effect on the increased expression of active transforming growth factor-beta (TGF-beta) in BAL. Batimastat treatment was effective in reducing MMP-2 and MMP-9 activity as well as the tissue inhibitor of metalloproteinase-1 (TIMP-1) level in BAL. These results suggest that administration of the MMP inhibitor batimastat is useful in preventing experimental pulmonary fibrosis induced by bleomycin and raises the possibility of a therapeutic approach to human pulmonary fibrotic disease.     

盐皮质激素受体在博来霉素诱导的实验性肺纤维化中的作用*

 目的：研究盐皮质激素受体（MR）在博来霉素诱导的实验性肺纤维化进展过程中的作用及机制。方法：将126只6～8周龄雄性C57BL/6小鼠随机分为对照组、博来霉素组和MR阻断剂螺内酯干预组,气管内一次性滴注博来霉素(2.5 mg/kg)溶液建立实验性小鼠肺纤维化模型,螺内酯干预组每天按螺内酯20 mg/kg经灌胃给药。于术后12 h、1 d、2 d、3 d、7 d、14 d和28 d处死小鼠,采用HE染色和Masson染色观察肺组织病理学变化及纤维化程度,采用real-time PCR检测各组肺组织中胶原1(Col1)、Col3、转化生长因子β(TGF-β)、单核细胞趋化蛋白1（MCP-1）及MR mRNA的表达水平。结果：（1）与对照组小鼠相比,博来霉素组及螺内酯干预组小鼠在滴注博来霉素后经历了典型的急性炎症期（12 h～3 d）、纤维化进展期（14 d）和纤维化晚期（28 d）。阻断MR下调早期炎症反应并减轻了纤维化程度。（2）螺内酯干预可以有效降低MR mRNA表达水平;阻断MR在急性炎症期显著下调MCP-1 mRNA的表达,在14 d显著下调TGF-β、Col1和Col3 mRNA表达水平。结论：(1）阻断MR可以明显减轻博来霉素诱导的肺纤维化程度;(2）阻断MR可能通过在急性炎症期调节MCP-1和TGF-β的表达,减轻炎症反应,并在纤维化进展期,下调TGF-β的表达,从而抑制肺纤维化的进展。     

依那西普抑制博来霉素诱导的小鼠肺纤维化

 目的：观察肿瘤坏死因子 α(TNF-α)拮抗剂依那西普对博来霉素诱导的肺纤维化小鼠的抑制纤维化作用,并探讨依那西普治疗肺纤维化的可能机制。方法：将45只SPF级雌性昆明小鼠随机分为3组：对照组（气管内雾化生理盐水）、纤维化组（气管内博来霉素3 mg/kg溶于100 μL生理盐水内雾化）和依那西普干预组（气管内雾化博来霉素后,4 mg/kg依那西普溶于100 μL生理盐水内腹腔注射,每3 d注射1次）。处理后第28 d收集样本,小鼠左肺置于10%中性甲醛固定,石蜡包埋切片后行HE与Masson染色;右肺碱水解法检测组织羟脯氨酸(HYP)的含量;酶联免疫法检测血清TNF-α和转化生长因子 β（TGF-β）的含量;提取肺组织总蛋白,Western blotting 检测磷酸化ERK1/2、JNK和p38的表达。结果：依那西普干预组肺组织病理损伤及气道上皮下胶原沉积较纤维化组减轻,肺叶炎症损伤评分和纤维化评分明显下降（均P<0.01）,肺组织HYP含量显著降低（P<0.05）,血清TNF-α 和TGF-β的浓度明显减少（均P<0.01）,肺组织ERK1/2、JNK和p38蛋白的磷酸化水平也显著下降（P<0.01,P<0.05,P<0.01）。结论：依那西普能显著下调TNF-α 和TGF-β的水平,从而抑制ERK1/2、JNK和p38的活化,缓解博来霉素诱导的小鼠肺纤维化病变。     

吉非替尼抑制博莱霉素诱导的小鼠肺纤维化

目的:观察吉非替尼对博莱霉素诱导的小鼠肺纤维化的抑制作用。方法:将40只SPF级雌性BALB/c小鼠分为4组:对照组(气管滴入生理盐水)、单纯口服吉非替尼组(吉非替尼灌胃200 mg/kg)、纤维化组(气管滴入博莱霉素3 mg/kg)、纤维化吉非替尼干预组(气管滴入博莱霉素+吉非替尼灌胃20 mg/kg)。实验第14 d杀鼠取肺,左肺石蜡切片行HE染色与Masson染色,免疫组化检测总表皮生长因子受体(EGFR)及磷酸化EG-FR;取右肺检测羟脯氨酸含量。结果:纤维化吉非替尼干预组肺病理损伤较纤维化组减轻,气道上皮下胶原沉积及肺羟脯氨酸含量减少(P0.05),气道上皮及肺间质细胞磷酸化EGFR表达评分下降(P0.05)。单纯口服吉非替尼组小鼠气道上皮下未见明显胶原沉积,肺羟脯氨酸含量及磷酸化EGFR表达评分与对照组相比无显著差异(P0.05)。结论:吉非替尼灌胃能显著抑制博莱霉素诱导的小鼠肺纤维化,大剂量(200 mg/kg)吉非替尼灌胃未引起明显肺纤维化。