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.     

IL-10 inhibits inflammation but does not affect fibrosis in the pulmonary response to bleomycin

Bleomycin yields pulmonary injury characterized by inflammation that proceeds to fibrosis. The production of IL-10 by pulmonary macrophages is increased in the inflammation that accompanies bleomycin lung injury. In the present study, IL-10 deficient and wildtype mice received 0.075 units of bleomycin intratracheally at day 0 and were sacrificed at day 7 or day 14. At day 7, pulmonary inflammation was increased in IL-10-deficient mice as reflected by increased representation of CD3+ and CD4+ lymphocytes and GR-1+ pulmonary granulocytes in the bronchoalveolar lavage (BAL) fluid. Pulmonary interstitial CD80+ and CD86+ mononuclear cells were increased in situ. At day 14, mononuclear cell inflammation was comparable between groups but pulmonary eosinophils were increased in the wildtype. There was no difference in the degree of pulmonary fibrosis, as judged by histology or lung hydroxyproline content. Lung chemokine expression of MIP-1alpha/beta, MIP-2, and eotaxin was increased at days 7 and 14 with a trend towards increased MCP-1 expression at day 14. The findings suggest an immunomodulatory role for IL-10 in the inflammatory response but not in the pulmonary fibrosis yielded by bleomycin.     

吡非尼酮和尼达尼布抑制博来霉素诱导的小鼠肺纤维化药效比较

目的:比较不同时期给予吡非尼酮和尼达尼布对博来霉素诱导的小鼠肺纤维化的作用。方法:根据给药时间和给药时长,建立5类小鼠模型:炎症时期给药模型、纤维化早期预防给药模型、纤维化早期治疗模型、纤维化晚期治疗模型和全程给药模型,分别检测炎症指标和纤维化指标。结果:(1)抗炎抗氧化评估:吡非尼酮和尼达尼布均能降低炎症细胞数目,抑制炎症因子分泌。吡非尼酮对白细胞介素1β(IL-1β)和IL-4的抑制效果较好(P<0.01),尼达尼布对IL-6、IFN-γ的抑制作用较好(P<0.05)。吡非尼酮可显著提高超氧化物歧化酶(SOD)活性(P<0.01),而尼达尼布可显著降低丙二醛(MDA)和髓过氧化物酶(MPO)含量(P<0.01)。(2)肺组织胶原含量检测:在纤维化早期治疗模型、纤维化晚期治疗模型、全程给药模型中,尼达尼布对羟脯氨酸的抑制作用均优于吡非尼酮(P<0.05)。而吡非尼酮在纤维化早期预防给药模型中对羟脯氨酸的抑制作用较好(P<0.01)。(3)肺组织病理学评价:吡非尼酮和尼达尼布均可减少肺组织炎症浸润和纤维化面积,抑制效果对比结果同胶原检测结果一致。结论...     

Inhibition of bleomycin-induced pulmonary fibrosis by lipopolysaccharide

Current evidence suggests that bleomycin toxicity may be attributable to its DNA degradative activity possibly via generation of free radicals and O2 metabolites as mediators. Since lipopolysaccharide (LPS) has been known to provide protection against O2 toxicity, which is correlated with increased activity of O2 metabolite-detoxifying enzymes, the effect of this agent on bleomycin-induced pulmonary fibrosis was examined. Endotracheal bleomycin administration caused increased lung collagen synthesis. A single intraperitoneal injection of LPS (500 micrograms/kg) at day zero significantly decreased these increases. Total bleomycin-induced lung collagen increase was also significantly reduced. LPS alone had no significant effect on total lung catalase activity. Glutathiione peroxidase activity, however, was significantly decreased by 15.8% compared to untreated animals at 2 days after LPS treatment and remained unchanged at other time points. In addition, superoxide dismutase activity was significantly elevated by 30% above untreated animals only at 14 days after LPS administration and remained unchanged at other time points. Endotracheal bleomycin administration alone caused significant reductions in catalase activity at 2 days and 2 weeks after treatment, whereas glutathione peroxidase activity increased above control untreated animals at 2 and 4 weeks, respectively. Superoxide dismutase activity was unaffected by bleomycin treatment. Pretreatment with LPS before bleomycin prevented these reductions or caused increases in the activities of these enzymes at 2 days. Glutathione peroxidase was increased and was significantly greater than those animals treated with bleomycin alone. Catalase also was higher in the LPS plus bleomycin group (by 22.2%, p less than 0.05) than the bleomycin group alone. Compared to the effects on lung collagen synthesis and content, LPS treatment resulted in much less dramatic changes in total lung antioxidant enzyme activities. This discrepancy between the intensity of LPS effects on lung O2 metabolite-detoxifying enzymes and that on pulmonary fibrosis implies that the LPS-ameliorating effect on pulmonary fibrosis could not be totally explained by increased ability to detoxify O2 metabolites. Rather, the data would favor the possibility that LPS inhibits bleomycin-induced pulmonary fibrosis either by its known immunosuppressive effects or some other unknown mechanism. The former would be in agreement with previous data which suggest that an intact immune response is necessary for complete expression of the fibrogenic response to bleomycin.     

T cell independence of bleomycin-induced pulmonary fibrosis

The role of T cells and cytokines in bleomycin (BLM)-induced fibrosis was evaluated in susceptible and resistant strains of normal and SCID mice. Histology and hydroxyproline analysis showed that BLM induced pulmonary fibrosis in C57BL/6 and (C57BL/6 x BALB/c)F1 mice, whereas BALB/c mice were resistant to the disease. To test whether lymphocytes were required for the induction of BLM-induced pulmonary fibrosis, SCID mice were injected intratracheally with BLM and evaluated for the development of pulmonary inflammation and fibrosis. Similar morphological changes and increases in hydroxyproline were observed in both C57BL/6 SCID and (C57BL/6 x CB.17)F1 SCID animals compared to those seen in wild-type C57BL/6 and (C57BL/6 x BALB/c)F1 mice. In contrast, CB.17 SCID mice, which are genetically similar to BALB/c mice, were resistant to disease induction. Analysis of the cellular infiltrate in BLM-treated C57Bl/6 SCID mice confirmed a lack of T cells in the lungs of SCID mice and demonstrated a pronounced accumulation of eosinophils in areas of developing pulmonary fibrosis. NK cells were significantly elevated in untreated SCID mice and did not increase further after BLM treatment. Analysis of selected cytokines 1 day after initiation of BLM-induced pulmonary fibrosis indicated that the levels of TNF-alpha and IFN-gamma appeared to segregate with fibrosis in both the SCID and wild-type mice. The data demonstrate that T cells are not required for the induction of fibrosis by BLM and suggest that responses by non-lymphoid cells may be sufficient for the induction of fibrosis.     

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.     

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。     

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。     

甘草酸对博莱霉素诱导的实验性肺纤维化的干预作用

目的:探讨甘草酸(GA)对博莱霉素(BLM)诱导的小鼠肺纤维化的干预作用及其可能机制。方法:将160只雄性C57BL/6J小鼠随机分为生理盐水(NS)组、BLM组、BLM+NS组和BLM+GA组。通过口咽气管吸入法吸入博莱霉素(2.5 mg/kg)建立实验性肺纤维化模型,BLM+GA组及BLM+NS组每天给予40 mg/kg甘草酸或等体积的生理盐水灌胃,于术后第3、7、14、21天取材。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,采用流式细胞术检测循环单核细胞和肺泡巨噬细胞的亚群比例变化,采用RT-qPCR检测肺组织中转化生长因子β1(TGF-β1)mRNA的表达水平,采用碱水解法检测肺组织中羟脯氨酸(HYP)含量。结果:与NS组相比,BLM组和BLM+NS组肺组织的炎症浸润及胶原含量明显增多,实验性肺纤维化模型制备成功。与BLM+NS组相比:BLM+GA组肺组织的炎症细胞浸润及胶原纤维沉积较少;第3、7天的Ly6C~(hi)单核细胞亚群比例和第7、14天肺泡巨噬细胞M2表型比例显著降低(P0.01);肺组织TGF-β1 mRNA表达量和HYP含量显著降低(P0.01)。结论:GA可以减轻博莱霉素诱导的小鼠肺组织的炎症反应和胶原纤维沉积,可能与GA对单核巨噬细胞的表型偏移和调控以及肺组织TGF-β1的表达下调有关。     

Treatment with chondroitinase ABC alleviates bleomycin-induced pulmonary fibrosis

Pulmonary fibrosis is characterized by an accumulation of inflammatory cells in the lung interstitium, followed by an increased deposition of extracellular matrix. Macrophages play a vital role in this disease by mediating the progression from inflammation to fibrosis, but the mechanisms by which macrophages are retained at these sites are not fully understood. Although the transmigration of leukocytes is regulated by chemokines, glycosaminoglycans modulate the function of chemokines and the migration of leukocytes. Accordingly, we investigated the role of chondroitin sulfate proteoglycans (CSPGs) in a murine bleomycin-induced pulmonary fibrosis models. After intratracheal injection of bleomycin or saline, mice were randomized to receive one intravenous injection and continuous infusion of the CSPG-digesting enzyme chondroitinase ABC (ChABC), or vehicle, for 7 days. CSPGs were readily induced and progressively augmented after the bleomycin challenge. Although CSPGs inhibited the early CCL2-dependent recruitment of macrophages, deposited CSPGs retained macrophages in fibrotic interstitium in a CD44-dependent manner. Treatment with ChABC in vivo dramatically increased survival of the mice and reduced collagen deposition by inhibiting persistent macrophage accumulation. These results indicate a pivotal role for CSPGs in macrophage-mediated lung fibrogenesis and suggest a possible new therapeutic role for ChABC in pulmonary fibrosis.     

Role of osteopontin in the pathogenesis of bleomycin-induced pulmonary fibrosis

Pulmonary fibrosis is initiated by migration, adhesion, and proliferation of fibroblasts. Osteopontin (OPN) is one of the cytokines produced by activated macrophages and mediates various functions, including cell attachment and migration, by interacting with alphav integrin. In this study, we have investigated the role of OPN in the pathogenesis of pulmonary fibrosis. We developed a mouse model for pulmonary fibrosis by intratracheal instillation of bleomycin (BLM). OPN was strongly expressed in alveolar macrophages accumulating in the fibrotic area of the lung. OPN messenger RNA (mRNA) in the lung was notably induced by BLM instillation, and the development of the fibrotic process was associated with an increase in the expression of OPN mRNA and protein. In vitro, recombinant OPN enhanced migration, adhesion, and platelet-derived growth factor (PDGF)-mediated DNA synthesis of murine fibroblast cell line NIH3T3. These effects of OPN on fibroblasts were significantly suppressed by addition of antimouse alphav integrin monoclonal antibody (RMV-7). Furthermore, treatment of mice with RMV-7 repressed the extent of pulmonary fibrosis in this model. Conclusively, these data suggest that OPN produced by alveolar macrophages functions as a fibrogenic cytokine that promotes migration, adhesion, and proliferation of fibroblasts in the development of BLM-induced pulmonary fibrosis.     

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。     

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.     

Improvement of bleomycin-induced pulmonary hypertension and pulmonary fibrosis by the endothelin receptor antagonist Bosentan

Rationale

There is evidence that endothelin plays a key role in the development of pulmonary hypertension (PH) in pulmonary fibrosis (PF). However, the functional consequence of the unselective endothelin receptor antagonist Bosentan in PH and PF has not yet been studied. Therefore, we investigated the effects of Bosentan on the development of PH in the model of Bleomycin-induced PF in rats.

Methods

Adult male Wistar rats were randomly assigned to the following groups: untreated animals (controls), Bleomycin-induced PF (Bleomycin) and Bleomycin-induced PF treated with Bosentan (Bleomycin + Bosentan). Exercise capacity was evaluated by treadmill exercise testing. PH was assessed by right ventricular systolic pressure (RVSP) and right ventricular hypertrophy. For quantification of PF the hydroxyproline content in lung tissue (HPC) was measured.

Results

Compared to controls, animals with Bleomycin-induced PF showed a significant reduction in exercise capacity (44% vs. 100%), significantly higher RVSP (65 mmHg vs. 23 mmHg), significantly more right ventricular hypertrophy (0.55 vs. 0.24) and significantly higher HPC (60.5 vs. 14.8). Bosentan treatment in animals with Bleomycin-induced PF resulted in significantly greater exercise capacity (98% vs. 44%) and a trend towards lower RVSP (52 mmHg vs. 65 mmHg), significantly less right ventricular hypertrophy (0.34 vs. 0.55) and significantly lower HPC (16.7 vs. 60.5) compared to untreated Bleomycin-induced PF.

Conclusion

Application of Bosentan in Bleomycin rats resulted in significantly higher exercise capacity as a result of improvements in PH and PF.     

Inhibition of activin receptor-like kinase 5 attenuates bleomycin-induced pulmonary fibrosis

Activin receptor-like kinase 5 (ALK5) is a type I receptor of transforming growth factor (TGF)-beta. ALK5 inhibition has been reported to attenuate the tissue fibrosis including pulmonary fibrosis, renal fibrosis and liver fibrosis. To elucidate the inhibitory mechanism of ALK5 inhibitor on pulmonary fibrosis in vivo, we performed the histopathological assessment, gene expression analysis of extracellular matrix (ECM) genes and immunohistochemistry including receptor-activated Smads (R-Smads; Smad2/3), CTGF, myofibroblast marker (alpha-smooth muscle actin; aSMA) and type I collagen deposition in the lung using Bleomycin (BLM)-induced pulmonary fibrosis model. ALK5 inhibitor, SB-525334 (10 mg/kg or 30 mg/kg) was orally administered at twice a day. Lungs were isolated 5, 7, 9 and 14 days after BLM treatment. BLM treatment led to significant pulmonary fibrotic changes accompanied by significant upregulation of ECM mRNA expressions, Smad2/3 nuclear translocation, CTGF expression, myofibroblast proliferation and type I collagen deposition. SB-525334 treatment attenuated the histopathological alterations in the lung, and significantly decreased the type I and III procollagen and fibronectin mRNA expression. Immunohistochemistry revealed that SB-525334 treatment showed significant attenuation in Smad2/3 nuclear translocation, decrease in CTGF-expressing cells, myofibroblast proliferation and type I collagen deposition. These results suggest that ALK5 inhibition attenuates R-Smads activation thereby attenuates pulmonary fibrosis.     

姜黄素抑制小鼠矽肺纤维化

目的： 建立小鼠矽肺动物模型,探讨姜黄素在减轻小鼠矽肺纤维化中的作用。方法: 用手术方法暴露小鼠气管,定量注射二氧化硅（SiO2）悬液建立矽肺模型。建模2周后将小鼠随机分为模型组、低剂量组、中剂量组和高剂量组分别给药,给药2周以及6周后处死动物,对肺组织行病理组织学检查。结果:建立了矽肺的纤维化模型。与模型组相比,给药2周后,高剂量组矽结节大小及数量显著减小(P<0.05);给药6周后,模型组以成纤维细胞为主,同时夹杂少量的胶原纤维,而给药组仍以巨噬细胞和淋巴细胞为主的细胞性矽结节为主。结论：姜黄素能抑制矽肺纤维化进程。     

博来霉素致大鼠肺纤维化模型肺组织的动态病理变化及其发生机制

目的： 了解博来霉素（BLM）致大鼠肺纤维化模型肺组织的动态病理变化,探讨BLM致肺纤维化的作用机制。方法：60只雄性SD大鼠采用随机数字表法分为正常对照组（N组）和肺纤维化模型组（B3、B7、B14、B28、B56组）,每组10只。除N组外,其余各组采用气管内注入BLM致大鼠肺纤维化模型, 分别于3、7、14、28、56 d处死各组大鼠,右肺行苏木精-依红（HE）、Masson胶原及天狼猩红染色,测定左肺羟脯氨酸（HYP）的含量。 RT-PCR法半定量测定转化生长因子-1（TGF-β1）、基质金属蛋白酶-9（MMP-9）和基质金属蛋白酶组织抑制物-1（TIMP-1）mRNA在肺内的表达。免疫组化法观察TGF-β1、MMP-9及TIMP-1蛋白在大鼠肺组织的表达。结果：(1) 模型组大鼠肺组织HYP含量显著高于N组（P<0.05）,模型组大鼠肺组织肺泡炎症的程度也明显重于N组,B14、B28和B56组大鼠肺纤维化的程度明显重于N组,大鼠在灌注BLM后不同时点其肺组织有着不同的病理变化。 (2) TGF-β1、MMP-9及TIMP-1在正常组大鼠肺脏中即有表达,但表达较弱,灌注BLM后它们的表达均增强,不同时点它们在肺组织内的分布有不同的特点。结论：给予后不同时点大鼠肺组织有着不同的病理变化特点,TGF-β1、MMP-9和TIMP-1在BLM诱导的肺纤维化形成过程中起着重要的调节作用。     

Localization of HSP47 mRNA in murine bleomycin-induced pulmonary fibrosis

Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that has been shown to play a major role in the processing and/or secretion of procollagen. However, the knowledge on which cells are actually synthesizing HSP47 in the lung parenchyma in pulmonary fibrosis was only limited. The aim of the present study was to investigate the localization of HSP47 messenger ribonucleic acid (mRNA) in normal lung and in the lungs of mice in bleomycin-induced pulmonary fibrosis, using in situ hybridization. For the purpose, ICR mice were intravenously injected with 10 mg/kg per day of bleomycin for five consecutive days. The lung cells expressing HSP47 mRNA were identified in control (saline alone) and bleomycin-treated mice by in situ hybridization. The signal for HSP47 mRNA was markedly increased in bleomycin-treated lungs compared with that of controls. HSP47 mRNA was localized in α-smooth-muscle-actin-positive myofibroblasts, surfactant-protein-A-positive type II pneumocytes, and F4/80-positive macrophages in the active fibrotic areas. These results suggest that these cells may synthesize procollagen in the fibrotic process of bleomycin-treated lungs through upregulation of HSP47 mRNA and play an important role in fibrogenesis.     

结缔组织生长因子在博莱霉素诱导的小鼠肺纤维化中的作用探讨

目的:检测结缔组织生长因子(CTGF)在小鼠肺内的表达,并探讨其在肺纤维化中的意义。方法:通过向气管内滴入博莱霉素建立小鼠肺纤维化模型。用免疫组化染色方法检测不同时期肺组织中CTGF蛋白的表达;用RT PCR检测CTGFmRNA的表达;用酸水解法测定肺羟脯氨酸的含量。结果:在正常小鼠肺组织中,CTGF蛋白和其mRNA几乎不表达;而在模型组的肺组织中表达明显升高(P<0.01)。CTGF蛋白表达于支气管/细支气管上皮细胞、肺泡Ⅱ型上皮细胞和肺成纤维细胞,表达量与肺组织中羟脯氨酸的含量呈显著的正相关(r=0.92,P<0.001)。结论:CTGF与肺纤维化的形成关系密切,CTGF检测可作为评价肺纤维化发生、发展的一种灵敏的指标。