阿司匹林对博莱霉素致大鼠肺间质纤维化的抑制作用及其机制

 目的  观察阿司匹林对博莱霉素所致大鼠肺间质纤维化的抑制作用,并探讨其作用机制。方法  取体质量250 g左右的健康清洁级雄性SD大鼠60只,随机分为生理盐水对照组、博莱霉素模型组、甲基强的松治疗组、阿司匹林治疗组,每组15只。生理盐水对照组经气管插管注入生理盐水0.2 mL,其他各组注入博莱霉素 5 mg/kg制备成模型。甲基强的松治疗组和阿司匹林治疗组每天灌胃给药分别予甲基泼尼松龙6 mg/kg、阿司匹林10 mg/kg,于第7、14、28天每组各处死5只,取其肺组织作以下测试:HE染色病理学观察;酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)检测羟脯氨酸、IL-4、TNF-α、转化生长因子β(transforming growth factor β,TGF β)和角化细胞生长因子(keratinocyte growth factor,KGF)水平;Real Time PCR检测TGF β的mRNA表达。结果  博莱霉素模型组大鼠肺组织在第7天时出现明显的出血渗出性炎症反应,在第28天时出现明显的肺组织纤维化;其肺组织的羟脯氨酸、IL-4和TNF-α水平较生理盐水对照组有明显升高(P<0.05),TGF-β蛋白和TGF β mRNA的表达也明显高于生理盐水对照组(P<0.01)。阿司匹林治疗组肺组织病理与博莱霉素模型组比较,第7天时大鼠肺组织的炎性渗出有明显减轻,第28天时肺组织纤维化程度较轻。阿司匹林治疗组大鼠肺组织的羟脯氨酸、IL-4、TNF-α含量较博莱霉素模型组有明显下降(P<0.01),其肺组织TGF-β蛋白含量和mRNA表达明显低于博莱霉素模型组(P<0.05)。阿司匹林治疗组与甲基强的松治疗组相比较,在第28天时肺组织羟脯氨酸含量低于甲基强的松治疗组(P<0.01),而IL-4、TNF-α、TGF-β、TGF-β mRNA的差异均无统计学意义(P>0.05)。结论  阿司匹林可抑制炎症细胞分泌TGF-β、IL-4和TNF-α,减轻博莱霉素导致的肺间质纤维化反应,其作用机制可能与下调TGF β mRNA和蛋白的表达有关。

Inhibitory effect and mechanism of aspirinin in the treatment of bleomycin-induced pulmonary fibrosis in rats

Objective  To observe the inhibitory effects of aspirin on SD rats with bleomycin induced pulmonary fibrosis,andto explore their mechanism.Methods  Sixty SPF class SD  rats with average weight of 250 g were randomly and equally divided into 4 groups:saline control group,bleomycin induced model group,methylprednisolone treatment group and aspirin treatment group.The rats of saline group were endotracheally intubated and injected with 0.2 mL of saline,other 3 groups were injected with bleomycin 5 mg/kg in order to induce lung fibrosis models.Then on the 7th,14th and 28th day,5 rats from each group were killed and their lung tissues were taken for the following tests:HE staining to observe pathological manifestations;ELISA to detect hydroxyproline IL-4,TNF-α,transforming growth factor β (TGF-β) and keratinocyte growth factor (KGF);Real Time PCR to detected mRNA expression of TGF-β.Results  Lung tissue of bleomycin induced model group had significant bleeding oozing inflammatory response on the 7th day and pulmonary fibrosis on the 28thday,and tissue hydroxyproline,IL-4 and TNF-α levels were significantly higher than that of saline control group (P<0.05).In the lung tissues of bleomycin induced model group,TGF-β protein and mRNA expressions were significantly higher compared with that of saline control group (P<0.01).Compared with bleomycin induced model group,the inflammatory exudate of lung tissue in aspirin treatment group was significantly alleviated on the 7th day,and there was a lesser extent of pulmonary fibrosis on the 28th day.Hydroxyproline,IL-4 and TNF-α of lung tissue in the aspirin treatment group were lower than that in bleomycin induced model group (P<0.01).In aspirin treatment group,TGF β protein and mRNA expressions in the lung tissues were significantly lower than that in bleomycin induced model group (P<0.05).Hydroxyproline content was significantly lower in aspirin treatment group than that in methylprednisolone treatment group on the 28th day (P<0.01),while there was no significant difference in IL-4,TNF-α,TGF-β  protein and mRNA between the two groups (P>0.05).Conclusions  Aspirin could inhibit inflammatory cells′ secretion of TGF-β,IL-4,TNF-α and reduce the reaction of bleomycin-induced lung fibrosis.The mechanism of inhibition of fibrosis might be associated with the down-regulation of TGF-β mRNA expression.