糜酶抑制剂对肺纤维化的干预作用及其机制研究

Effect of chymase inhibitor on bleomycin-induced pulmonary fibrosis and its mechanism in rats

目的观察糜酶抑制剂对博莱霉素(BLM)致大鼠肺纤维化模型干预作用及对糜酶、转化生长因子-1β(TGF-β1)mRNA表达的影响,并探讨糜酶参与肺纤维化的机制。方法健康SD雌性大鼠60只随机分3组:正常对照组(生理盐水)、模型组(博莱霉素)、干预组(博莱霉素+糜酶抑制剂),每组20只。分别在第7、14、21、28天处死,每组检测5只大鼠,观察支气管肺组织病理改变,支气管肺泡灌洗液(BALF)白细胞计数及分类,逆转录-聚合酶链反应(RT-PCR)法检测肺组织糜酶和TGF-β1mRNA表达的含量。结果①干预组、模型组较对照组肺泡炎程度明显加重,但干预组和模型组相差不明显;②干预组、模型组较对照组纤维化明显增高,干预组较模型组纤维化明显减轻;③干预组和模型组大鼠的BALF中白细胞总数、巨噬细胞、中性粒细胞及淋巴细胞构成与对照组差异有统计学意义(P<0,01),干预组的中性粒细胞在第7和14天比模型组减少(P<0,01,P<0,05);④模型组和干预组肺组织中糜酶、TGF-β1的mRNA的表达持续增强,与对照组比较差异有统计学意义(P<0,01),干预组比模型组表达明显减少(P<0,01)。结论糜酶抑制剂能减轻博莱霉素诱导的大鼠肺纤维化,其主要机制是通过下调糜酶、TGF-β1的mRNA的表达发挥作用。

Objective To explore the effect of chymase inhibitor on bleomycin-induced pulmonary fibrosis and chynase mRNA and transforming growth factor-β1 （TGF-β1） mRNA expressions in rats. Methods Sixty female rats were randomly divided into three groups： the model group, the control group and chymase inhibitor（Chy-I） treatment group in which the rats were intratra- cheally instilled with 5 mg/kg bleomycin. From the first day after bleomycin challenge, every day, in the chymase inhibitor treatment group 10 mg/kg chymase inhibitor was perfused into the stomach, and the other groups were given sterile saline. Five rats were killed in each group on the 7th, the 14th, the 21st day and the 28th day. The pathological changes of lung tissues and the total and different white blood cells of bronchoalveolar lavage fluid（BALF） were determined by hematoxyhn-eosin staining. mRNA expressions of chymase and TGF-β1 in pulmonary tissues were determined by reversal transcription-polymerase chain reaction（RT-PCR）. Results （1） Alveolitis in the model and the Chy-I groups were significantly lower than in the control group, but there was no significant different between the model and the Chy-I groups. （2） Pulmonary fibrosis was evidently inhibited after chymase inhibitor treatment. （3） Total white blood cells and percentage of macrophages, lymphocyte and neutrophils in BALF were significantly increased in the model group and the Chy-I group as compared with the control group. On the 7th and 14th days, neutrophils was significant increased in the Chy-I group as compared with the model group. （4） mRNA expression levels of chymase and TGF-β1 were evidently inhibited after chymase inhibitor treatment, and they were higher in the lung fibrosis of the model group than in the control group, also they were significantly lower in the Chy-I group than in the model group. Conclusion Chymase inhibitor can alleviate bleomycin-induced pulmonary fibrosis in rats by inhibiting mRNA expressions of chymase and TGF-β1 in lung tissues.