酸吸入致大鼠肺纤维化初步探索

目的研究实验性酸吸入与大鼠肺间质纤维化的相关性及其可能的作用机制,并与传统的博来霉素致纤维化作一比较。方法健康雄性SD大鼠120只,随机分为正常对照组、博来霉素组、高浓度盐酸组、中浓度盐酸组和低浓度盐酸组,每组24只。博来霉素组气管内一次性注入博来霉素诱导纤维化,盐酸组每周气管内滴注不同浓度盐酸1次,正常对照组每周气管内滴注生理盐水1次。各组分别于造模后第7、14、28及42天随机处死6只,取肺组织行HE、Masson染色评价肺组织病理变化,用RT-PCR方法测定肺组织转化生长因子β1(TGF-β1)的mRNA表达,用免疫组化的方法半定量测定I型胶原蛋白、结缔组织生长因子(CTGF)的表达。结果盐酸组肺泡炎程度始终显著高于对照组,在开始2周内达到一个高峰,随后仍旧维持一个相对较高状态,28d达到或者超过博来霉素组水平。盐酸组纤维化程度随时间逐渐增强,显著高于对照组,但始终未超过博来霉素组。盐酸组肺组织TGF-β1mRNA在28d时达到博来霉素组水平,至42d时全面超过博来霉素组水平。博来霉素组大鼠各时间点肺组织I型胶原表达均显著高于正常阴性对照组及3个盐酸组。高、中浓度盐酸组CTGF表达从14d起高于正常阴性对照组,且随滴注次数及时间增加而增强。结论本实验从一个角度反映了经常性胃食管酸反流引起的酸吸入与肺纤维化的相关性,为揭示胃食管反流病(GERD)与特发性肺纤维化(IPF)的关系提供了初步的实验室证据。

Correlation of Experimental Acid Aspiration and Pulmonary Fibrosis in Rats

Objective To study the pathology and possible mechanism of experimental hydrochloric acid（HCl） inhalation induced pulmonary fibrosis in rats and make a comparison with traditional bleomycin-induced fibrosis. Methods 120 male SD rats were randomly divided into nomal control group,bleomycin group,high-dose HCl group,middle-dose HCl group and low-dose HCl group. The bleomycin group was intratracheally injected bleomycin once to induce pulmonary fibrosis. The three HCl groups were intratracheally injected HCl once per week. The control group was given saline in the same way. Six rats of each group were randomly sacrificed on day 7,14,28 and 42,respectively. The histological changes of the lung tissue were evaluated by HE and Massons trichrome staining. The mRNA expression of transforming growth factor-β1 （ TGF-β1 ） was assayed by RT-PCR,and the CTGF and collagen type I protein expressions were analyzed by immunohistochemistry . Results The hydrochloride group had a significantly higher extent of alveolitis （ P〈0. 01 ）, reaching a peak at the first 2 weeks,and then still maintained at a relatively high status,and from 28 d to reach or exceed that in the bleomycin group. Hydrochloric acid group fibrosis gradually increases over time,significantly higher （P〈0. 01 or 0. 05）,but not consistently exceeded that in the bleomycin group （P〉0. 05）. Similar results appeared in the TGF-β1 mRNA,I-collagen and CTGF expression in immunohistochemical assessment. Conclusion The results of this study indicate from the point of view a relationship between recurrent gastro-esophageal acid reflux caused by acid inhalation and pulmonary fibrosis,and provides preliminary experimental evidence for the relationship between gastroesophageal reflux disease （GERD） and idiopathic pulmonary fibrosis （IPF）.