红霉素对大鼠肺纤维化的预防作用及其可能机制

Prophylactic effect of erythromycin on bleomycin-induced pulmonary fibrosis in rats

目的 观察红霉素对肺纤维化大鼠的预防效果并对其机制进行探讨.方法 将60只SD大鼠随机分为5组,即生理盐水对照组（A组）、博莱霉素组（B组）、博莱霉素十红霉素预处理组（C组）、博莱霉素十红霉素同时处理组（D组）、博莱霉素十红霉素后处理组（E组）.C组、D组、E组分别在博莱霉素给药的前3天、当天、后7天开始以红霉素100mg/kg每日灌胃,而A组和B组分别每日灌胃等体积的生理盐水.各组动物大鼠在造模14 d、28 d分2次取材,每次各组随机处死6只,共30只.肺组织Masson染色观察肺泡炎和肺纤维化改变,免疫组织化学SP法和逆转录PCR测定肺组织中转化生长因子β1、Smad3、α-平滑肌肌动蛋白的蛋白及其mRNA的表达,对二甲氨基苯甲醛法检测肺组织匀浆中羟脯氨酸的含量.结果 ①红霉素治疗组大鼠各时间点的肺泡炎和肺纤维化程度均较B组减轻,D组和E组比较差异无统计学意义,但均不及C组.②B组转化生长因子β1和α-平滑肌肌动蛋白的蛋白及其mRNA以及Smad3 mRNA的表达增加,B组Smad3在细胞浆的表达显著减少,细胞核的表达增加,红霉素处理组上述改变减轻;D组和E组比较差异无统计学意义,但均不及C组.结论 红霉素对大鼠肺纤维化形成有一定的预防作用,可能与抑制TGF-β1/Smad3信号通路的激活、抑制成纤维细胞增殖转型、减少肺泡间质胶原的沉积有关.

Objective To evalulate the effects and molecular mechanism of erythromycin （EM） in preventing experimental pulmonary fibrosis in rats.Methods Sixty healthy male SD rats were randomly divided into five groups：control group （group A）,bleomycin group （group B）,bleomycin and EM pretreatment group （group C）,bleomycin and EM syntreatment group （group D）,bleomycin and EM post-treatment group （group E）.EM was administrated by oral at a dose of 100 mg/kg from day-3,0,7 to the rats respectively in the group C,D,and E.The equivalent volume of normal saline was administrated by oral to the rats in the group A and B.All experimental animals were sacrificed on day 14 and 28,six rats each time,a total of 30,and the lung specimens were harvested for Masson stain to observe pulmonary alveolitis and lung fibrosis.The content of hydroxyproline was measured by alkaline hydrolysis,While the expressions of protein and mRNA of transforming growth factor-β1 （TGF-β1）,Smad3 and α-smooth muscle actin （α-SMA） were analyzed by immunohistochemistry and reverse transcriptase polymeric chain reaction.Results The area of alveolar septum and collagen in the lungs as well as the collagen production inereased in group B which were attenuated by EM.There was no statistical siganificance between group D and group E.The protein and mRNA expressions of TGF-β1 and α-SMA as well as Smad3 mRNA were increased in group B and were attenuated by EM.The expression of Smad3 in plasma in group B was attenuated while in nucleus enhanced.Smad3 expression decreased in nucleus but enhanced in plasma.The change in group C was the most obvious,while there was no statistieal significance beteen group D and group E.Conclusions EM can prevent the development of pulmonary fibrosis in rats,which might due to influce the signaling mediated by TGF-β1/Smad3 and then inhibit the lung fibroblasts proliferation and collagen production.