氟伐他汀对大鼠肺间质纤维化及通气功能的影响

背景肺间质纤维化病理上可见以成纤维细胞(fibroblast,Fb)为主的大量间质细胞的增生及胶原分泌的增多,氟伐他汀对Fb等多种细胞具有增殖抑制作用.目的观察氟伐他汀对体外培养的大鼠肺Fb增殖的抑制作用和对博来霉素诱发的大鼠肺纤维化及肺通气功能的影响.单位解放军第四军医大学西京医院呼吸内科;解放军第四军医大学基础部病理学教研室;解放军第四军医大学西京医院骨科研究所.设计随机对照实验研究.材料本实验于200101/12在解放军第四军医大学西京医院呼吸内科实验室完成.实验选用健康雄性一级SD大鼠31只.干预取1只大鼠,摘取其肺组织,体外培养大鼠肺Fb,加入氟伐他汀,MTT法观察对培养细胞生长曲线的影响及不同浓度(0,1×10-7,1×10-6,1×10-5,1×10-4,1×10-3,1×10-2mol/L,氟伐他汀0 mol/L为空白对照组)的氟伐他汀对培养细胞的抑制作用;计数法观察氟伐他汀对大鼠肺Fb分裂指数的影响;羟脯氨酸比色法检测氟伐他汀对培养的大鼠肺Fb胶原分泌的影响.随机将另30只大鼠分为正常对照组、博来霉素组及氟伐他汀组.氟伐他汀组根据治疗开始时间为模型制备后第1,15天和给药剂量为20,10mg/kg(高、低剂量)分为4个治疗组第1天高、低剂量组,第15天高、低剂量组.28d后处死动物,肺组织作HE、Masson和苦味酸天狼猩红染色,图像分析半定量测定并比较肺泡间隔Fb数量、肺泡间隔厚度、间质面积,肺组织匀浆测定组织胶原含量.主要观察指标氟伐他汀对体外培养的大鼠肺Fb生长曲线、分裂指数及培养上清液胶原含量的影响;氟伐他汀对博来霉素诱导的肺纤维化大鼠肺泡间隔Fb数量、肺泡间隔厚度、间质面积、肺组织胶原含量的影响.结果氟伐他汀对体外培养的大鼠肺Fb具有明显抑制作用(t=4.20～17.52,P<0.01),并随着药物剂量的增大其抑制作用逐渐增强,呈剂量依赖效应,1×10-4mol/L的氟伐他汀已可使培养细胞的增殖受到完全抑制,自第2天起各时间点A490值与第1天比较,差异无显著性意义(P>0.05);细胞分裂指数、培养细胞的胶原分泌在氟伐他汀的作用下也有明显降低(t=8.037,P<0.01;t=3.99～10.84,P<0.05或P<0.01).博来霉素组在肺泡间隔Fb数量、肺泡间隔厚度、肺间质面积及肺组织胶原含量均高于对照组(t=4.62～11.93,P<0.01),氟伐他汀组各组以上各观察指标均不同程度低于博来霉素组(t=2.69～7.65,P<0.05～0.01);博来霉素组基质胶原及Ⅰ,Ⅲ型胶原分布较对照组明显增多,氟伐他汀治疗组各组均有不同程度的减少.结论氟伐他汀对体外培养的大鼠肺Fb的增殖具有明显的抑制作用,并呈剂量依赖效应;氟伐他汀对博来霉素诱发的大鼠肺纤维化具有显著的治疗作用,并且早期治疗较晚期效果更为明显.

Effect of fluvastatin on pulmonary interstitial fibrosis and ventilation function in rats

BACKGROUND: The pathological characteristics of pulmonary interstitial fibrosis are the proliferation of a large number of fibroblasts and the increasing deposition of matrix collagen that takes the place of normal lung structure. Fluvastatin can inhibit the proliferation of fibroblasts and many other cells.OBJECTIVE: To investigate the effects of fluvastatin in inhibiting the proliferation of rat lung fibroblasts cultured in vitro and its influence on bleomycin-induced pulmonary fibrosis and ventilation function.DESIGN: A randomized controlled trial.SETTING: Department of Respiratory Diseases, Xijing Hospital, Fourth Military Medical University of Chinese PLA; Teaching and Research Section of Pathology, Department of Basic Medicine, Fourth Military Medical University of Chinese PLA; Research Institute ofOrthopedics, Xijing Hospital,Fourth Military Medical University of Chinese PLA.PARTICIPANTS: The study was conducted in the laboratory of Department of Respiratory Diseases, Xijing Hospital of Fourth Military Medical University of Chinese PLA from January to December 2001. Thirty-one healthy adult male Sprague-Dawley(SD) rats of grade Ⅰ were selected in this study.INTERVENTIONS: The fibroblasts derived from the lung normal of one rat were cultured in vitro in media containing fluvastatin. The effect of fluvastatin on the growth curve and the effect of its different concentrations(0, 1 × 10-7,1 ×10-6, 1 ×10-5, 1 ×10-4, 1 ×10 3and 1 ×10-2 mol/L, fluvastatin of 0 mol/L was taken as the blank control group) in inhibiting the cultured cells were observed with MTT colorimetry. The effect of fluvastatin on the division index of the fibroblasts was analyzed by direct cell counting Hydroxyproline colorimetry was used to detect the influence of fluvastatin on the collagen secretion in the media. The other 30 SD rats were divided into six groups: normal control group, bleomycin-induced group and fluvastatin-treated groups(TH 1,TE1, TH15 and TL15 groups) named according to the date of giving fluvastatin,i. e. the 1st day and the 15th day, after the rats were given bleomycin A5. All the rats were killed 28 days later. The number of fibroblasts, the thickness of alveolar wall and the area of mesenchyma in lung tissue were measured by HE staining. The extracellular matrix and collagen in lung tissue were observed by Masson and sirius red staining, and hydroxyproline in lung tissue homogenates was measured.MAIN OUTCOME MEASURES: Fibroblast growth curve and division index of rat lung, hydroxyproline in the media and lung tissue homogenates,number of fibroblasts and the thickness of alveolar wall, the area of mesenchyma, extracellular matrix and collagen contents in lung tissue.RESULTS: Fluvastatin could inhibit the proliferation of the rat lung fibroblasts cultured in vitro(t=4.20 to 17.52, P < 0.01), and its inhibitory effect was increased with the increased dose of fluvastatin, which showed a dose-dependent effect. The 1 × 10-4 mol/L fluvastatin could completely inhibit the proliferation of the cultured cells, and the A490 value from the 2nd day on the fibroblasts by MTT colorimetry was not insignificantly different from those on the 1st day( P > 0.05) . The division index of the fibroblasts and secretion of collagen were obviously decreased by fluvastatin( t = 8. 037,P <0.01; t =3.99 to 10. 84, P <0.05 or P <0.01). In vivo, the number of fibroblasts, the thickness of lung alveolar wall, the area of mesenchyma and the content of hydroxyproline in lung tissue were significantly higher in bleomycin group than in control group( t =4. 62 to 11.93, P < 0. 01), while those in the fluvastatin-treated groups were lower than those in bleomycin group in different degrees( t = 2.69 to 7.65, P < 0.05 to 0.01 ) . The distribution of extracellular matrix and types Ⅰ and Ⅲ collagen in lung tissue were obviously increased in bleomycin group as compared with that in control group, but decreased in different degrees in fluvastatin-treated groups.CONCLUSION: Fluvastatin can significantly inhibit the proliferation of rat lung fibroblasts in vitro, suggesting that it may be an effective drug for pulmonary fibrosis. Treatment at earlier stage is more effective than at advanced stage.