苦参碱减轻百草枯诱导的模型小鼠肺纤维化

目的 探讨苦参碱对百草枯(PQ)诱导的小鼠肺纤维化的影响及其可能的作用机制。方法 将小鼠随机分为对照组、百草枯(PQ)组、苦参碱组。百草枯(18 mg/kg)单次腹腔注射以建立肺纤维化模型。苦参碱组建模24 h后,予以苦参碱(100 mg/kg)灌胃干预。28 d后取小鼠肺组织,用HE染色观察肺组织炎性反应情况;用Masson染色观察肺组织纤维化情况并进行Ashcroft评分,用碱水法检测各组小鼠肺组织中羟脯氨酸(HYP)的含量;用Western blot检测胶原蛋白Ⅰ(collagenⅠ)、胶原蛋白Ⅲ(collagenⅢ)的表达;用免疫荧光法检测上皮细胞间充质转化(EMT)相关蛋白[α-平滑肌蛋白(α-SMA)、上皮性钙黏附蛋白(E-cardherin)、波形蛋白(vimentin)]的表达。结果 百草枯组模型小鼠肺组织结构破坏明显,可见胶原纤维沉积,肺纤维化评分较对照组升高(P<0.001),且百草枯能够显著上调EMT相关蛋白的表达水平;而经苦参碱干预后可减轻肺纤维化病理改变,降低肺组织中羟脯氨酸、胶原蛋白Ⅰ、胶原蛋白Ⅲ含量(P<0.001),抑制α-SMA、vimen...     

银杏叶提取物对大鼠肺纤维化初期肺结缔组织生长因子表达的影响

目的：　研究银杏叶提取物（GbE）对博莱霉素(BLM)性肺纤维化初期大鼠肺内结缔组织生长因子(CTGF)表达的影响。方法： 气管内滴注BLM, 用Western blotting法检测肺组织CTGF含量；用氯胺-T法测定肺组织羟脯氨酸含量；用比色法检测血浆丙二醛(MDA)含量。结果： 注BLM后14 d肺组织CTGF含量和出肺血MDA含量， BLM+NS组均分别高于NS组(P<0.05; P<0.01)。注BLM后30 d肺组织羟脯氨酸含量和出肺血MDA含量，BLM+NS组均分别高于NS组(Both P<0.01)。GbE处理可显著缓解上述变化。结论： GbE缓解BLM性肺纤维化初期肺内CTGF上调; GbE的抗氧化损伤作用可能是其缓解CTGF增多的机制之一。     

苦参碱对肺纤维化鼠肝细胞生长因子表达的影响

目的 探讨苦参碱对博莱霉素诱导肺纤维化大鼠肺组织肝细胞生长因子表达的影响.方法 选取SD大鼠72只,随机分为空白对照组、模型对照组、苦参碱处理组,每组各24只.各组动物于7、14、28d随机处死8只,取肺组织采用苏木精-伊红染色,Masson胶原染色及测定羟脯氨酸(HYP)浓度采评价治疗效果,用原位杂交的方法检测肝细胞生长因子(HGF)mRNA的表达,用酶联免疫吸附法(ELISA)检测HGF蛋白在大鼠肺组织的含量.结果 苦参碱组肺泡炎和肺纤维化程度及羟脯氨酸浓度低于同时期模型对照组,有统计学意义;模型组肺组织HGFm RNA表达及蛋白含量在第7d达高峰,之后下降,第14d,第28d低于正常对照组(P<0.01),苦参碱组HGFm RNA表达及蛋白含量变化趋势与模型组同,但其表达均高于同时间段模型组(P<0.05).结论 在博来霉素诱导肺纤维化形成阶段应用苦参碱干预能减轻肺纤维化的程度,其可能机制为通过促进HGF的表达而实现.     

MyD88基因缺失型与野生型小鼠在博莱霉素诱导肺纤维化过程中的病理学比较

目的探讨小鼠体内My D88在博莱霉素(bleomycin,BLM)诱导肺纤维化后的表达变化,从而进一步探索肺纤维化的发病机制。方法利用BLM分别诱导My D88基因缺失型与野生型小鼠肺纤维化,HE、Masson染色检测肺部纤维化程度,Western blot检测野生型小鼠模型My D88蛋白的表达变化,并测定肺组织中羟脯氨酸含量。结果基因缺失型小鼠模型肺纤维化程度均轻于野生型,野生型造模组小鼠My D88表达量及羟脯氨酸含量均明显高于对照组(P0.05),My D88基因缺失型小鼠造模组羟脯氨酸含量与对照组相比差异无统计学意义。结论 My D88在博莱霉素诱导肺纤维化进程中有一定的促进作用。     

依那西普对博莱霉素所致小鼠肺纤维化的影响及其机制

目的:观察依那西普对博莱霉素诱导的小鼠肺纤维化的作用及可能机制。方法:方法将30只SPF级雄性昆明小鼠随机分为3组,即对照组、模型组、干预组,每组10只。对照组小鼠气管内灌注生理盐水,模型组小鼠气管内灌注博莱霉素5 mg/kg,干预组小鼠气管内灌注博莱霉素后,3 mg/kg依那西普腹腔注射,一周2次。于造模后28 d处死小鼠,收集肺组织,碱水解法检测羟脯氨酸含量;肺组织用4%多聚甲醛固定后,石蜡包埋切片,行HE染色及Masson染色;Western blot法检测肺组织NF-κB和磷酸化NF-κB的表达。结果:干预组小鼠肺组织羟脯氨酸含量较模型组明显下降(P0.01);干预组肺组织炎症评分较模型组明显下降(P0.01),肺纤维化评分较模型组下降(P0.01);干预组肺组织磷酸化NF-κB的表达下降(P0.01)。结论:依那西普可抑制NF-κB的磷酸化,减轻博莱霉素导致的小鼠肺部炎症程度和纤维化改变,延缓肺纤维化进展。     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠矽肺的结缔组织生长因子和ERK1/2表达的调节作用

目的:探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对大鼠矽肺纤维化模型肺组织中胶原含量、结缔组织生长因子(CTGF)和细胞外信号调节激酶 1/2(ERK1/2)表达的影响.方法:选用非暴露式气管灌注法复制大鼠矽肺模型,并给予AcSDKP,采用羟脯氨酸测量法定量分析肺组织中总胶原蛋白的含量,免疫组织化学法、免疫印迹法检测肺组织内CTGF、phospho-ERK1/2及ERK1/2蛋白的表达.结果:AcSDKP治疗组胶原含量低于相对应的矽肺模型组.与相应的对照组相比,矽肺模型组大鼠肺组织内CTGF、phospho-ERK1/2蛋白表达均增加;与相应矽肺模型组相比,给予AcSDKP后,大鼠肺组织内CTGF、phospho-ERK1/2蛋白表达均明显降低.而各组间比较ERK1/2蛋白表达无明显改变.结论:AcSDKP可能通过阻断ERK1/2途径抑制了CTGF的表达,从而发挥抗矽肺纤维化的作用.     

灵菌红素对小鼠肺纤维化及其对Wnt/β-catenin信号通路的影响

目的观察灵菌红素对小鼠肺纤维化的改善作用,探讨Wnt/β-catenin信号通路的调控机制。方法C57BL/6小鼠随机分为对照组(Control group)、博来霉素组(Bleomycin group)和灵菌红素组(Peptide group),每组15只。除对照组外,其余各组小鼠气管内分别一次性注入100μL博莱霉素溶液(5mg/kg)以制备小鼠肺纤维化模型;造模完成后,治疗组分别腹腔注射300μg/kg灵菌红素或300 mg/kg吡非尼酮,连续28天。HE及Masson染色观察肺组织病理变化;测定肺组织羟脯氨酸含量;Western Blot检测肺组织中TGF-β1、α-SMA、Colla I、CollaⅢ及GSK-3β、p-GSK-3β、α-catenin蛋白的表达。结果灵菌红素明显改善小鼠肺组织病理损伤,降低肺组织中羟脯氨酸含量,下调TGF-β1、α-SMA、Colla I、CollaⅢ、p-GSK-3β及β-catenin蛋白表达水平,上调GSK-3蛋白表达水平。结论灵菌红素改善小鼠肺纤维化,与抑制Wnt/β-catenin信号通路活性相关。     

大黄酸通过抑制miR-21而干预TGF-β1/Smad通路并减轻博莱霉素所致大鼠肺纤维化

目的:观察大黄酸(rhein,RH)对博莱霉素所致肺纤维化大鼠微小RNA-21(miR-21)表达以及转化生长因子β1(TGF-β1)/Smad通路的影响。方法:博莱霉素一次性气管内注射复制大鼠肺纤维化模型,随机分为RH低、中、高剂量组及模型(model)组;正常对照组大鼠气管内注射生理盐水。用药28 d后,HE染色观察各组大鼠肺组织形态学的变化;测定肺系数、肺组织羟脯氨酸含量;real-time PCR检测肺组织中miR-21和TGF-β1/Smad7m RNA表达;Western blot法分析TGF-β1和Smad7蛋白的表达。结果:与model组相比,RH用药组大鼠的肺泡炎及肺纤维化程度有明显降低,肺系数及肺组织羟脯氨酸含量也显著减少,肺组织中miR-21表达下降,TGF-β1的m RNA和蛋白表达水平也明显下降,Smad7的mRNA及蛋白表达水平明显增高(P0.05)。结论:RH抗肺纤维化的作用可能与抑制miR-21的表达,从而干预TGF-β1/Smad信号通路,减少细胞外基质沉积有关。     

姜黄素对哮喘小鼠气道炎症和肺内诱导型一氧化氮合酶的影响

目的探讨姜黄素对哮喘小鼠气道炎症和肺内诱导型一氧化氮合酶的影响。方法36只BALB/c小鼠随机分为对照组、哮喘组和姜黄素组,用卵蛋白作为致敏原制备哮喘小鼠模型,对支气管肺泡灌洗液(BALF)细胞总数及嗜酸性粒细胞计数,硝酸还原酶法检测肺组织iNOS活性及NO含量,免疫组织化学和Western blot方法检测大鼠支气管上皮细胞iNOS蛋白表达,双抗体夹心法检测肺组织白细胞介素-4(IL-4)及干扰素-γ(IFN-γ)的表达水平。结果姜黄素干预可显著降低哮喘小鼠BALF中细胞总数及嗜酸粒细胞计数与肺组织iNOS活性及NO含量,减轻炎症反应。免疫组织化学和Western blot结果显示,姜黄素组小鼠支气管上皮细胞iNOS蛋白表达显著低于哮喘小鼠(P0.01)。结论姜黄素可降低哮喘小鼠气道炎症及iNOS表达水平,提示姜黄素对于哮喘可能有潜在的治疗作用。     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对转化生长因子β1和Smad7表达调节在大鼠硅肺纤维化形成过程中的作用

目的:探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对大鼠硅肺纤维化模型肺组织中胶原含量、转化生长因子β1(TGF-131)和Smad 7表达的影响.方法:选用非暴露式气管灌注法制作大鼠硅肺模型,并给予AcSDKP.采用H-E染色进行形态学观察,胶原Van Gison染色观察硅肺结节与间质纤维化的形成及改变,羟脯氨酸法检测肺内总胶原含量,免疫组织化学法、免疫印迹法检测肺组织内TGF-β1、Smad7蛋门的表达.结果:染尘大鼠肺内硅结节形成明显,硅肺模型制作成功.AcSDKP治疗组肺组织胶原含量低于硅肺模型组.与对照组相比,模型组大鼠肺组织内TGF-β1蛋白表达增加,Smad7蛋白表达降低;与模型组相比.给予AcSDKP后,人鼠肺组织内TGF-β1蛋白表达明显降低,Smad7蛋白表达增高.结论:AcSDKP可能通过增加大鼠肺组织中Smad7蛋白的表达米抑制TGF-β1信号转导,从而发挥抗硅肺纤维化的作用.     

当归注射液及前列腺素E_2对结缔组织生长因子在大鼠肺纤维化模型中表达作用的比较研究

目的探讨结缔组织生长因子(CTGF)在大鼠肺间质纤维化中的表达及其在25%当归注射液、前列腺素E2(dmPGE2)的肺脏保护作用中的意义。方法SD大鼠随机分为对照组、模型组、当归组、PGE2组。按博莱霉素(BLM)5mg/kg体重复制大鼠肺纤维化模型,当归组、dmPGE2组术后分别给于25%当归注射液(腹腔内注射)、dmPGE2(肌肉注射),于第28天处死全部大鼠。制备大鼠肺组织切片,用原位杂交及免疫组化SABC法分别检测CTGF mRNA、纤维连结蛋白(FN)和Ⅲ型胶原(Col-Ⅲ)在肺内的表达,HE染色评价肺纤维化程度。结果模型组CTGF mRNA、FN和Col-Ⅲ的表达及肺纤维化程度明显高于对照组(P<0.01),而当归组及PGE2组明显低于模型组(P<0.01)。两治疗组间比较,除CTGF外,其余指标无显著性差异(P>0.05),各组指标的相关分析表明,CTGF表达水平与肺纤维化程度(r=0.886;P<0.01)、FN(r=0.836;P<0.01)和Col-Ⅲ(r=0.918;P<0.01)呈正相关关系。结论25%当归注射液可能通过下调CTGF而减轻肺间质纤维化。     

结缔组织生长因子在大鼠肺纤维化模型中的蛋白表达

目的 :了解结缔组织生长因子 (connectivetissuegrowthfactor ,CT GF)在大鼠肺纤维化模型中的表达状况及其与肺纤维化之间的关系。方法 :42只Wistar大鼠随机分为二组。模型组 (M组 ) :气管内灌注博莱霉素 ,对照组 (C组 ) :气管内灌注生理盐水。于灌注后第 7、14、2 8天每组分别处死大鼠 7只。制备大鼠肺组织切片。用免疫组化SABC法分别检测二组大鼠肺组织中CTGF及转化生长因子 β1 (TGF β1 )、纤维连接蛋白 (FN )在肺内的表达水平。结果 :M组CTGF及TGF β1 、FN在肺内的表达水平在各时间点均显著高于C组 (P <0 .0 5 )。结论 :CTGF作为TGFβ1 的下游因子 ,可能通过促进细胞外基质(ECM)如FN和胶原蛋白等合成而在博莱霉素诱导的肺纤维化形成过程中起重要作用     

Immunomodulation of experimental pulmonary fibrosis by intravenous immunoglobulin (IVIG)

OBJECTIVES: To assess the immunomodulatory effect of intravenous immunoglobulin (IVIG) using an experimental model of bleomycin-induced pulmonary fibrosis. METHODS: Pulmonary fibrosis was induced in C57BL/6 mice by direct intratracheal injection of bleomycin. Mice were treated with IVIG 1 week prior to (prevention protocol), or 10 days following bleomycin injection, when the disease was in progress. The controls used in the study included mice given phosphate buffered saline (PBS) and mice subjected to a commercial individual-IgG. Collagen-I deposits in the affected lungs were detected by Sirius red staining of paraffin embedded lung sections. The collagen-I content was measured by employing the hydroxyproline assay. RESULTS: Prevention of bleomycin-induced pulmonary fibrosis by IVIG has been demonstrated by reduced expression of collagen-I protein in the affected lungs. The hydroxyproline levels in the lungs of the IVIG-treated mice were 214.33 +/- 13.56 microg/1 g tissue, compared to the higher levels in lungs of IgG treated mice (342.44 +/- 35.60 microg/1 g tissue) or untreated controls 328.00 +/- 45.55 microg/1 g tissue, (p < 0.0001). Effective treatment of bleomycin-induced pulmonary fibrosis by IVIG has been demonstrated by the reduced expression of collagen-I protein in the affected lungs, detected by sirius red histological staining. The hydroxyproline levels in the lungs of the IVIG-treated mice were 261.00 +/- 18.81 microg/1 g tissue, in comparison to the higher levels in the lungs of the IgG treated mice (342.43 +/- 32.89 microg/1 g tissue) and of untreated controls (344.33 +/- 49.85 microg/1 g tissue), (p < 0.001). CONCLUSIONS: Based on these preliminary studies, we conclude that IVIG may have a beneficial effect in the down regulation of collagen-I levels in the lungs of mice with bleomycin-induced pulmonary fibrosis.     

Direct thrombin inhibition reduces lung collagen, accumulation, and connective tissue growth factor mRNA levels in bleomycin-induced pulmonary fibrosis

Dramatic activation of the coagulation cascade has been extensively documented for pulmonary fibrosis associated with acute and chronic lung injury. In addition to its role in hemostasis, thrombin exerts profibrotic effects via activation of the major thrombin receptor, protease-activated receptor-1. In this study, we examined the effect of the direct thrombin inhibitor, UK-156406 on fibroblast responses in vitro and on bleomycin-induced pulmonary fibrosis in rats. UK-156406 significantly inhibited thrombin-induced fibroblast proliferation, procollagen production, and connective tissue growth factor (CTGF) mRNA levels when used at equimolar concentration to the protease. Thrombin levels in bronchoalveolar lavage fluid and expression of thrombin and protease-activated receptor-1 in lung tissue were increased after intratracheal instillation of bleomycin. The characteristic doubling in lung collagen in bleomycin-treated animals (38.4 +/- 2.0 mg versus 17.1 +/- 1.4 mg, P < 0.01) was preceded by significant elevations in alpha1(I) procollagen and CTGF mRNA levels (3.0 +/- 0.4-fold and 6.3 +/- 0.4-fold respectively, (P < 0.01), and total inflammatory cell number. UK-156406, administered at an anticoagulant dose, attenuated lung collagen accumulation in response to bleomycin by 35 +/- 12% (P < 0.05), inhibited alpha1(I) procollagen and CTGF mRNA levels by 50% and 35%, respectively (P < 0.05), but had no effect on inflammatory cell recruitment. This is the first report showing that direct thrombin inhibition abrogates lung collagen accumulation in bleomycin-induced pulmonary fibrosis.     

人脐带间充质干细胞对新生鼠肺纤维化的防治作用**

背景：间充质干细胞因具有自我增殖、多向分化潜能和旁分泌等功能,成为慢性肺部疾病细胞替代治疗的研究热点。 目的：探讨人脐带间充质干细胞对新生大鼠肺纤维化的防治作用及对正常肺发育的影响。 方法：将32只新生2 d SD大鼠随机数字表法均分为PBS对照组、人脐带间充质干细胞组、博来霉素对照组,博来霉素+人脐带间充质干细胞组,后两组腹腔注射博来霉素建立肺纤维化模型,2个细胞组于第7天腹腔注射人脐带间充质干细胞。 结果与结论：博来霉素对照组羟脯氨酸水平最高,肺纤维化最严重,与其他3组比较差异均有显著性意义(P < 0.05);博来霉素干预的两组辐射状肺泡计数和肺组织匀浆中的转化生长因子β1 mRNA表达均低于其他两组(P < 0.05),但血管内皮生长因子mRNA表达升高(P < 0.05),给予细胞治疗后,上述指标均有好转(P < 0.05)。说明人脐带间充质干细胞能过旁分泌增加血管内皮生长因子mRNA表达,下调转化生长因子β1 mRNA水平,对肺纤维化起保护作用。另外,正常鼠腹腔注射脐带间充质干细胞后辐射状肺泡计算无明显变化,证实其对新生鼠肺发育无明显影响。      

Beneficial effects of early (but not late) intervention of heme oxygenase-1 on bleomycin-induced pulmonary fibrosis in mice

The aim of this study is to explore the effects of early and late intervention in heme oxygenase-1 (HO-1) expression or activity on pulmonary fibrosis in mice. Mice were divided into four groups: one control and three bleomycin hydrochloride-induced groups in which mice were administered phosphate-buffered saline (PBS), hemin or Cr (III) mesoporphyrin IX chloride (CrMP). Early intervention with hemin, an HO-1 inducer, abrogated bleomycin-induced pulmonary fibrosis (fibrotic/reparative score decrease from 21.0±2.4 to 13.8±1.7, P<0.01), and early intervention with CrMP, an HO-1 inhibitor, worsened bleomycin-induced pulmonary fibrosis (fibrotic/reparative score increase from 21.0±2.4 to 32.5±2.9, P<0.01). Elevated glutathione expression and reduced expression of TGF-β1, hydroxyproline, LDH and MDA were seen in the lungs of the early hemin intervention group compared to that seen in the PBS group (P<0.05). These results taken together show that HO-1 can prevent or ameliorate pulmonary fibrosis and oxidative stress and inflammation at an early stage of pulmonary fibrosis.     

Immunomodulation of experimental pulmonary fibrosis by intravenous immunoglobulin (IVIG)

Objectives: To assess the immunomodulatory effect of intravenous immunoglobulin (IVIG) using an experimental model of bleomycin-induced pulmonary fibrosis.

Methods: Pulmonary fibrosis was induced in C57BL/6 mice by direct intratracheal injection of bleomycin. Mice were treated with IVIG 1 week prior to (prevention protocol), or 10 days following bleomycin injection, when the disease was in progress. The controls used in the study included mice given phosphate buffered saline (PBS) and mice subjected to a commercial individual-IgG. Collagen-I deposits in the affected lungs were detected by Sirius red staining of paraffin embedded lung sections. The collagen-I content was measured by employing the hydroxyproline assay.

Results: Prevention of bleomycin-induced pulmonary fibrosis by IVIG has been demonstrated by reduced expression of collagen-I protein in the affected lungs. The hydroxyproline levels in the lungs of the IVIG-treated mice were 214.33 ± 13.56 μg/1 g tissue, compared to the higher levels in lungs of IgG treated mice (342.44 ± 35.60 μg/1 g tissue) or untreated controls 328.00 ± 45.55 μg/1 g tissue, (p < 0.0001). Effective treatment of bleomycin-induced pulmonary fibrosis by IVIG has been demonstrated by the reduced expression of collagen-I protein in the affected lungs, detected by sirius red histological staining. The hydroxyproline levels in the lungs of the IVIG-treated mice were 261.00 ± 18.81 μg/1 g tissue, in comparison to the higher levels in the lungs of the IgG treated mice (342.43 ± 32.89 μg/1 g tissue) and of untreated controls (344.33 ± 49.85 μg/1 g tissue), (p < 0.001).

Conclusions: Based on these preliminary studies, we conclude that IVIG may have a beneficial effect in the down regulation of collagen-I levels in the lungs of mice with bleomycin-induced pulmonary fibrosis.     

Connective tissue growth factor is crucial to inducing a profibrotic environment in "fibrosis-resistant" BALB/c mouse lungs

The individual susceptibility to pulmonary fibrosis (PF) remains a mystery, suggesting a role for genetic predisposition. The pathogenesis of PF involves a multitude of factors mediating crosstalk between various tissue components. Some factors, such as transforming growth factor beta, are recognized as key elements in the process, whereas the role of others, such as connective tissue growth factor (CTGF), is unclear. We investigated if Balb/c mice, known to be fibrosis resistant partly due to lack of CTGF induction upon stimulation with bleomycin, can be transformed into fibrosis-sensitive individuals by generation of a CTGF-rich environment using transient overexpression of CTGF by adenoviral gene transfer (AdCTGF). We show that AdCTGF is not sufficient to cause fibrosis, and that bleomycin challenge results in inflammation, but not fibrosis, in Balb/c mouse lungs. This inflammation is accompanied by lower levels of CTGF and tissue inhibitor of metalloproteinase-1 gene expression compared with fibrosis-prone C57BL/6 mice. However, concomitant administration of AdCTGF and bleomycin leads to a persistent upregulation of tissue inhibitor of metalloproteinase-1 gene and a significant fibrotic response in Balb/c similar to that in C57BL/6 mice. We propose that CTGF is an important mediator in the pathogenesis of PF in that it provides a local microenvironment in the lung that causes individual susceptibility. CTGF should be considered as a novel drug target and as a potential marker for identifying individuals at risk.     

Bleomycin injury of the lung in a mast-cell-deficient model

Lung mast cell hyperplasia and fibrosis is induced by bleomycin lung injury. The role of the mast cell in this process of injury and resultant fibrosis is unclear. Mutant mi/mi mice, profoundly mast-cell-deficient, were treated with intraperitoneal bleomycin and demonstrated minimal acute inflammatory and chronic fibrotic responses. Lung histamine values determined at 14 and 42 days after bleomycin injury in mi/mi mice were not increased compared to untreated mi/mi animals. However, lung histamine levels in normal mice demonstrate a 300% increase over controls on Day 14 after bleomycin injury, and then returned to baseline by Day 42. The mi/mi BAL cell recovery at 2 weeks after injury and lung hydroxyproline levels at 4 weeks after injury were not altered from baseline. The normal litter mates, in contrast, demonstrated significant increases compared to controls in both of these parameters (p<0.01,p<0.04). Although the mi/mi mouse is also deficient in basophils, natural killer cells and functional osteoclasts, there is no evidence of lowered pulmonary defense mechanism and neutrophils and alveolar macrophages are present in normal numbers. This investigation supports the hypothesis that the mast cell contributes to bleomycin-induced lung injury and fibrosis.