Effects of Different Doses of Atorvastatin on Pulmonary Fibrosis of Rats
作者： 张晓萍 导师：邵润霞 年度:2010 院校： 郑州大学
KeywordsAtorvastatin, Pulmonary fibrosis, Transforming growth factor-β1, Connective tissue growth factor, Bleomycin
背景及目的肺纤维化原因不明,发病机制不清,近年来其发病率和病死率均呈明显上升趋势,但临床疗效较差,所以,本研究拟采用博莱霉素(bleomycin, BLM)一次性气管内滴入的方法复制大鼠肺纤维化模型,探讨转化生长因子β1(transforming growth factor-β1, TGF-β1)和结缔组织生长因子(connective tissue growth factor, CTGF)在肺纤维化形成中的作用及不同剂量阿托伐他汀对博莱霉素所致肺纤维化大鼠的治疗作用。材料和方法健康雌性SD大鼠75只随机分为5组,每组15只：对照组、模型组、10 mg/kg治疗组、20 mg/kg治疗组、40 mg/kg治疗组。模型组和治疗组动物均一次性气管内灌注BLM (5 mg/kg),对照组灌注等体积生理盐水；治疗组于灌注BLM后第2d始按照分组剂量每日给予阿托伐他汀灌胃治疗,对照组和模型组给予生理盐水灌胃。各组均于造模后1周、2周、4周分别随机选取5只动物腹主动脉采血查动脉血气,随后处死取肺组织,HE染色了解肺泡炎情况,Masson染色了解肺纤维化情况,免疫组化检测肺组织中TGF-β1和CTGF表达的变化。结果病理结果提示在造模后1周肺泡炎最明显,造模后2周肺泡炎仍存在,并且出现早期纤维化改变,造模后4周呈现明显的纤维化改变；各时间点大鼠动脉血氧分压(Pa02)均随治疗剂量增大逐渐升高,同一组内则随时间延长逐渐升高；肺组织中TGF-β1和CTGF的表达量随时间延长逐渐减少,各时间点治疗组TGF-β1和CTGF的表达量均较模型组明显减少,且治疗剂量越大TGF-β1和CTGF的表达减少越明显。以上数据差异均具有统计学意义(P<0.05)。结论经口气管插管BLM一次性气管内注入的方法可成功复制大鼠肺纤维化模型,且损伤小,成功率高；TGF-β1和CTGF参与肺纤维化的发病过程,且两者的表达呈明显的正相关；阿托伐他汀对博莱霉素所致的肺纤维化大鼠具有明显的治疗作用,且呈剂量依赖性和疗程依赖性,其机制可能与减少肺组织TGF-β1和CTGF的表达有关。
Backgroud and ObjectivesPulmonary fibrosis is a disease whose origin and pathogenesy are unknown. Recently, it was reported that both incidence rate and case-fatality rate of pulmonary fibrosis upgrade obviously. But there are still no available therapeutic methods now. Therefore my research in which the method of instilling bleomycin in trachea one time is used to mimic the modle of pulmonary fibrosis of rats is to observe the effects of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) on pulmonary fibrosis and the therapeutic effects of different doses of atorvastatin on bleomycin (BLM)-induced pulmonary fibrosis of rats.Materials and MethodsSeventy-five healthy female SD rats were randomly divided into five groups (15 rats in each group) ie. normal group; bleomycin-induced pulmonary fibrosis model group; atorvastatin (10mg/kg)-treated group; atorvastatin (20mg/kg)-treated group; atorvastatin (40mg/kg)-treated group. Rats in model group and atorvastatin-treated groups were instilled with bleomycin in trachea (5 mg/kg), and rats in normal group were instilled with equal normal saline; rats in atorvastatin-treated groups were lavaged with different doses of atorvastatin each day from the second day after instillation, and rats in non-atorvastatin-treated groups were lavaged with normal saline. Five rats in each group were chosen randomly on the 1st week,2nd week and 4th week after bleomycin instillation, and the blood was drawn from abdominal aorta to test blood gas analysis and lung tissue samples were harvested for histopathology study. The extent of alveolus inflammation and pulmonary fibrosis was determined by HE and Masson staining respectively and the protein levels of TGF-β1 and CTGF in pulmonary tissues were determined by histoimmunochemical stain.ResultsFrom the HE and Masson staining we found that the extent of alveolus inflammation was the strongest one week after bleomycin instillation and earlier pulmonary fibrosis was found two weeks after bleomycin instillation, then typical pulmonary fibrosis example was established successfully four weeks after bleomycin instillation. The arterial partial pressure of oxygenare (PaO2) of rats steped up gradually with the increase of therapeutic dose at each time point and steped up with the prolongation of time in the same group. The protein levels of TGF-β1 and CTGF in pulmonary tissues decreased gradually with the prolongation of time. The expression of TGF-β1 and CTGF were significantly lower in atorvastatin-treated groups than that in modle group at each time point. The more doses of therapeutic, the less expression of TGF-β1 and CTGF. There was significent difference between each group (P<0.05).ConclusionsThe modle of pulmonary fibrosis of rats can be established successfully by the method of instilling bleomycin in trachea through oral trachea cannula one time. Both TGF-β1 and CTGF play important role in the development of pulmonary fibrosis, and the expressions of TGF-β1 and CTGF are in remarkable positive correlation. The therapeutic effect of atorvastatin on bleomycin-induced pulmonary fibrosis of rats is remarkable, which is dependent on the dose and course of treatment.