辛伐他汀对大鼠肺纤维化及其内皮间质变过程的影响

Effects of simvastatin on pulmonary fibrosis and endothelial-mesenchymal transition in the pulmonary fibrosis tissue of rats

目的:观察辛伐他汀对大鼠肺纤维化及其内皮间质变(EnMT)过程中VE-钙粘素(VE-cad)、波形蛋白(VIM)、α-平滑肌蛋白(α-SMA)表达的影响。方法:健康雄性SD大鼠60只,随机分为对照组(A组)、造模组(B组)、辛伐他汀5 mg治疗组(C组)、辛伐他汀10 mg治疗组(D组),每组各15只。博来霉素(BLM)按5 mg/kg剂量一次性气管内灌注复制博莱霉素致大鼠肺纤维化模型,从造模第1日起C、D组每天分别胃内灌注辛伐他汀混悬液5 mg/(kg·d)及辛伐他汀混悬液10 mg/(kg·d),A组和B组每天胃内灌注等体积生理盐水10 ml/(kg·d)。于造模第7、14和28日随机处死各组大鼠5只。Masson染色观察大鼠肺组织形态变化;碱性水解法检测肺组织中羟脯氨酸(HYP)含量;免疫组化法测定各组大鼠肺组织血管新生微血管密度(MVD);免疫组化和逆转录-聚合酶链反应法测定各组肺组织中VE-Cad、VIM及α-SMA蛋白和mRNA的表达水平。结果:①与A组相比,B、C、D组各时间点肺组织HYP和MVD水平、VIM、α-SMA的mRNA和蛋白表达水平均明显升高(P均<0.05),且以28 d达最高;而相应时间点VE-Cad的mRNA和蛋白表达水平均明显降低(P均<0.05),且以28 d达最低。②与B组相比,C、D组HYP和MVD水平、VIM、α-SMA的mRNA和蛋白表达水平均有降低(P均<0.05),以D组28 d下降最明显;而相应时间点VE-Cad的mRNA和蛋白表达水平均有升高(P均<0.05),以D组28 d升高最明显。结论:辛伐他汀可减轻大鼠肺纤维化,其机制可能与增强VE-cad表达,降低VIM及α-SMA表达,减少EnMT发生有关。

Objective:To investigate the effects of simvastatin(SIM)on pulmonary fibrosis and the expression of VE-cadherin(VE-cad),vimentin(VIM)and alpha-smooth muscle actin(α-SMA)in the pulmonary fibrosis tissue of rats.Methods:Sixty healthy male SD rats were randomly divided into control group(group A),bleomycin group(group B),5 mg SIM group(group C)and 10 mg SIM group(group D),15 rats in each group.The model of rat pulmonary fibrosis was established by itraperitoneal injection of bleomycin(5 mg/kg).Since the first day of modeling,the rats of group C and D were treated with simvastatin suspension 5 mg/(kg·d)and 10 mg/(kg·d)by intragastric administration everyday,and the rats of group A and B were treated with equal volume of saline 10 ml/(kg·d)everyday.Five rats of each group were sacrificed randomly at the 7th,14th and 28th day.Masson staining was used to observe the morphological changes of lung tissue in rats.The degree of fibrosis in lung tissues of each group was evaluated by the content of hydroxyproline(HYP).The microvessel density(MVD)was analyzed by immunohistochemistry,The expressions of protein and mRNA of VE-cad,VIM andα-SMA were determined by immunohistochemistry and RT-PCR.Results:①Compared with group A,the levels of HYP and MVD,the mRNA and protein expression levels of VIM andα-SMA in lung tissues of groups B,C and D were increased significantly at the 7th,14th and 28th day(all P<0.05),which reached highest level at the 28th day.However,the mRNA and protein expression levels of VE-CAD were decreased significantly at the corresponding time(P<0.05),which reached lowest level at 28th day.②Compared with group B,the levels of HYP and MVD,the mRNA and protein expression levels of VIM andα-SMA in groups C and D were decreased at the 7th,14th and 28th day(all P<0.05),which were decreased more obviously in group D at the 28th day.However,the mRNA and protein expression levels of VE-CAD were increased at the corresponding time(all P<0.05),which were increased more obviously in group D at the 28th day.Conclusion:Simvastatin can reduce the degree of pulmonary fibrosis in rats through inhibiting the process of EnMT,which can enhance the expression of VE-cad and reduce the expression of VIM andα-SMA.