leukotriene-c4 and Pulmonary-Fibrosis

Synthesis of cysteinyl leukotrienes (cys-LT) is thought to cause inflammatory disorders such as bronchial asthma and allergic rhinitis. Recent reports have suggested that leukotriene C4 (LTC4 ) is an important regulator of pulmonary fibrosis. This study examined the effect of LTC4 in LTC4 synthase-overexpressed transgenic mice with bleomycin-induced pulmonary fibrosis. The function of lung-derived fibroblasts from transgenic mice was also investigated.. Bleomycin was administrated to transgenic mice and wild-type (WT) mice by intratracheal instillation. Concentrations of interleukin (IL)-4 and -13, interferon-γ, and transforming growth factor (TGF)-β1 in bronchoalveolar lavage fluid were measured 1, 3, 7 and 14 days after the administration of bleomycin. Lung tissue was examined histopathologically on day 14. In addition, lung-derived fibroblasts from transgenic and WT mice were cultured for 7 days. Expression of TGF-β1 mRNA was measured by real-time polymerase chain reaction.. Both the pathological scores for pulmonary fibrosis (3.8 ± 0.4 vs 2.0 ± 0.1, P < 0.05) and the levels of IL-4 (12.1 ± 2.3 vs <7.8 pg/mL, P < 0.05), IL-13 (26.5 ± 5.2 vs <7.8 pg/mL, P < 0.01) and TGF-β1 (211.1 ± 30.2 vs 21.3 ± 1.2 pg/mL, P < 0.01) on day 14 were significantly greater in transgenic than in WT mice. Furthermore, the reduction of LTC4 by pranlukast hydrate, a cys-LT1 receptor antagonist, in fibroblasts from transgenic significantly (P < 0.05) decreased the expression of TGF-β1 mRNA (by ∼50%) compared with those from WT mice.. Overexpression of LTC4 , amplifies bleomycin-induced pulmonary fibrosis in mice. Our findings suggest a role for LTC4 in lung fibrosis.

Topics: Animals; Bleomycin; Cells, Cultured; Disease Models, Animal; Glutathione Transferase; Interferon-gamma; Interleukin-13; Interleukin-4; Leukotriene C4; Lung; Mice; Mice, Inbred BALB C; Mice, Transgenic; Pulmonary Fibrosis

To observe the effects of three different doses of polydatin (PD) on pulmonary interstitial fibrosis in rats induced by bleomycin.. One hundred and twenty-nine healthy Sprague-Dawley rats three months old, were randomly divided into six groups. Group A: normal control group; group B: model group treated with bleomycin (pretreatment with saline 1 mL x kg(-1) intraperitoneally before bleomycin); group C: PD 10 mg x kg(-1) (pretreatment with PD 10 mg x kg(-1) intraperitoneally before bleomycin); group D: PD 20 mg x kg(-1) (pretreatment with PD 20 mg x kg(-1) intraperitoneally before bleomycin); group E: PD 40 mg x kg(-1) (pretreatment with PD 40 mg x kg(-1) intraperitoneally before bleomycin), group F: dexamethason (DXM) treated group (pretreatment with saline 1 mL x kg(-1) intraperitoneally before bleomycin and then with DXM 1 mg x kg(-1) x d(-1)). At day 3, 7, 14, 28 after injection of bleomycin, eight rats in each group were randomly chosen to be killed. The right lungs of dead rats were removed and appropriately processed for hematoxylin and eosin (H&E) stain, histologically observed under light microscope. The hydroxyproline content and the PLA2 activity in pulmonary homogenate were measured with alkaline hydrolysis assay and acid modified microtitrimetic method. The levels of leukotriene C4 (LTC4), prostaglandin E2 (PGE2), transforming growth factor-beta1 (TGF-beta1) in bronchoalveolar lavage fluid (BALF) were measured with enzyme-linked immunosorbent assay (ELISA).. At day 3, 7, 14, 28 after intratracheal instillation of bleomycin in rats of group B, the PLA2 activity in lung homogenate and the levels of its metabolic products PGE2, LTC4 as well as TGF-beta1 in BALF increased significantly compared with those in group A (P < 0.01). And lung hydroxyproline concentration began to grow up markedly at day 7 compared with those in group A (P < 0.05), reaching its maximum at day 28. Compared with group B, three different doses of PD and DXM significantly reduced the activity of the PLA2 and hydroxyproline concentration in lung homogenate as well as the levels of PGE2, LTC4, TGF-beta1 in BALF at various periods (P < 0.05). There was statistically significant difference between three different doses of PD groups (P < 0.05). And the group E (PD 40 mg x kg(-1)) was lower than group D (PD 20 mg x kg(-1)), group D was lower than group C (PD 10 mg x kg(-1)) (respectively, P < 0.01). Group E and DXM group were no significant difference. However, all these observation parameters were higher than the normal level (compared with group A, P < 0.01). Histological studies revealed that it was showed less inflammation and a lower degree of fibrosis in the lungs treated with PD than bleomycin model group.. PD has the protective effect on pulmonary interstitial fibrosis. However, it can't completely block the process of pulmonary fibrosis.

Topics: Animals; Bleomycin; Dinoprostone; Drugs, Chinese Herbal; Female; Glucosides; Leukotriene C4; Male; Phospholipases A2; Pulmonary Fibrosis; Rats; Rats, Sprague-Dawley; Stilbenes

To characterize the role of GM-CSF in pulmonary fibrosis, we have studied bleomycin-induced fibrosis in wild-type mice vs mice with a targeted deletion of the GM-CSF gene (GM-CSF-/- mice). Without GM-CSF, pulmonary fibrosis was worse both histologically and quantitatively. These changes were not related to enhanced recruitment of inflammatory cells because wild-type and GM-CSF-/- mice recruited equivalent numbers of cells to the lung following bleomycin. Interestingly, recruitment of eosinophils was absent in GM-CSF-/- mice. We investigated whether the enhanced fibrotic response in GM-CSF-/- animals was due to a deficiency in an endogenous down-regulator of fibrogenesis. Analysis of whole lung homogenates from saline- or bleomycin-treated mice revealed that GM-CSF-/- animals had reduced levels of PGE2. Additionally, alveolar macrophages were harvested from wild-type and GM-CSF-/- mice that had been exposed to bleomycin. Although bleomycin treatment impaired the ability of alveolar macrophages from wild-type mice to synthesize PGE2, alveolar macrophages from GM-CSF-/- mice exhibited a significantly greater defect in PGE2 synthesis than did wild-type cells. Exogenous addition of GM-CSF to alveolar macrophages reversed the PGE2 synthesis defect in vitro. Administration of the PG synthesis inhibitor, indomethacin, to wild-type mice during the fibrogenic phase postbleomycin worsened the severity of fibrosis, implying a causal role for PGE2 deficiency in the evolution of the fibrotic lesion. These data demonstrate that GM-CSF deficiency results in enhanced fibrogenesis in bleomycin-induced pulmonary fibrosis and indicate that one mechanism for this effect is impaired production of the potent antifibrotic eicosanoid, PGE2.

Topics: Animals; Bleomycin; Cell Division; Dinoprostone; Drug Administration Schedule; Granulocyte-Macrophage Colony-Stimulating Factor; Indomethacin; Injections, Intramuscular; Injections, Intraperitoneal; Intubation, Intratracheal; Kinetics; Leukocyte Count; Leukotriene C4; Lipid Metabolism; Lipids; Macrophages, Alveolar; Mice; Mice, Inbred C57BL; Mice, Knockout; Monocytes; Prostaglandins; Pulmonary Fibrosis; Sodium Chloride

Idiopathic pulmonary fibrosis (IPF) is a progressive disorder characterized by inflammation, fibroblast proliferation, and accumulation of extracellular matrix proteins. Leukotrienes (LTs) are pro-inflammatory and pro-fibrogenic mediators derived from the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism. They are thought to play a role in a number of disease processes, but have received relatively little attention in investigations into the pathogenesis of IPF. In this study, we measured the levels of immunoreactive LTs B(4) and C(4) in homogenates of lung tissue obtained from patients with newly diagnosed, untreated IPF, as compared to levels measured in homogenates of uninvolved nonfibrotic lung tissue from patients undergoing resectional surgery for bronchogenic carcinoma. Compared to homogenates on nonfibrotic control lung, homogenates from IPF patients contained 15-fold more LTB(4) and 5-fold more LTC(4). IPF homogenate levels of LTB(4) were significantly correlated with histologic indices of both inflammation (r=0.861) and fibrosis (r=0.926). Activation of 5-LO is known from in vitro studies to be associated with localization of the enzyme at the nuclear membrane. Immunohistochemical staining for 5-LO protein in alveolar macrophages (AMs) demonstrated that such an "activated" localization pattern was significantly more frequent in IPF lung (19.2+/-3.3% of cells) than in control lung (9.3+/-0.9%); this localization pattern was rarely seen (3.2%) in sections from a truly normal transplant donor lung. Consistent with these data, AMs obtained from IPF patients by bronchoalveolar lavage, purified by adherence, and cultured in the absence of a stimulus for 16 h elaborated significantly greater amounts of LTB(4) and LTC(4) than did control AMs obtained from normal volunteers. These data indicate that the 5-LO pathway is constitutively activated in the lungs of patients with IPF, and the AM represents at least one cellular source of LT overproduction in this disorder. We speculate that LTs participate in the pathogenesis of IPF, and their overproduction in this disorder may be amenable to specific pharmacotherapy.

Topics: Adult; Aged; Arachidonate 5-Lipoxygenase; Cells, Cultured; Enzyme Activation; Female; Humans; Immunohistochemistry; Inflammation; Leukotriene B4; Leukotriene C4; Lung; Lung Neoplasms; Macrophages, Alveolar; Male; Middle Aged; Pulmonary Fibrosis; Smoking