沙利度胺灌胃对烟雾暴露致大鼠肺间质纤维化合并肺气肿的影响及其机制

Effects of thalidomide on pulmonary interstitial fibrosis complicated with emphysema induced by smoke exposure in rats and its mechanism

目的观察沙利度胺灌胃对烟雾暴露致大鼠肺间质纤维化合并肺气肿的影响并探讨其机制。方法将120只SD大鼠随机分为对照组、烟雾暴露组、沙利度胺组、阳性药物对照组各30只。烟雾暴露组、沙利度胺组、阳性药物对照组分别置于玻璃容器内进行烟雾暴露,沙利度胺组于烟雾暴露第1天给予沙利度胺溶液灌胃,阳性对照组于烟雾暴露第1天腹腔内注射氢化可的松,共暴露30 d;对照组置于相同容器内呼吸新鲜空气。分别于烟雾暴露第7、15、30天,通过股动脉放血处死各组大鼠10只,采用HE染色及Masson染色观察各组各时点肺组织病理改变,采用ELISA法检测各组各时点血清转化生长因子β_(1)(TGF-β_(1))、血管内皮生长因子(VEGF)、肿瘤坏死因子α(TNF-α)水平。结果HE染色结果显示,对照组大鼠肺泡腔结构正常,肺泡腔内无明显炎症及纤维化的呈现。烟雾暴露组大鼠在第7天时病变部位肺泡扩张,肺泡内可见红细胞及炎症细胞,同时伴大量成纤维细胞渗出;第15天时可见炎症细胞减少,肺上叶部分肺泡持续扩张,成纤维细胞大量增多;第30天时可见肺大疮与肺间质纤维化交替存在。沙利度胺组及阳性药物对照组在各时点肺组织病理改变与烟雾暴露组大体相同,但肺泡炎症、纤维化及肺大疮程度明显减轻。Masson染色结果显示,对照组大鼠右下肺组织中细胞外基质出现少许胶原纤维被染成蓝色。烟雾暴露组在第7天时出现肺泡上皮损伤和上皮下基底膜破坏,中、下肺部出现胶原纤维,可见少量染成蓝色的胶原纤维;第15天时肺泡壁厚度增加,形成纤维化及大量瘢痕组织,可见大量染蓝的胶原纤维;第30天时上肺大疮较前变化不大,下肺可见大量肺泡壁破坏融合,可见大量密集的蓝色胶原纤维。与烟雾暴露组比较,沙利度胺组和阳性药物对照组胶原含量均减少,肺大疮严重程度减低。各组大鼠同时点血清TGF-β_(1)、VEGF、TNF-α水平比较,烟雾暴露组>阳性药物对照组、沙利度胺组>对照组(P均<0.05),沙利度胺组与阳性药物对照组同时点TGF-β_(1)、VEGF、TNF-α水平差异无统计学意义。结论沙利度胺灌胃可减轻烟雾暴露所致大鼠肺间质纤维化合并肺气肿,其机制可能与减轻炎症反应及抑制新生血管生成有关。

Objective To observe the effect of intragastric administration of thalidomide on pulmonary interstitial fi-brosis complicated with emphysema induced by smoke exposure in rats and to explore its mechanism.Methods Totally 120 SD rats were randomly divided into the control group,smoke exposure group,thalidomide group,and positive drug control group,with 30 rats in each group.The rats in the smoke exposure group,thalidomide group and positive drug con-trol group were respectively placed in glass containers for smoke exposure for 30 days.The rats in the thalidomide group were given thalidomide solution by gavage on the first day of smoke exposure,and the rats in the positive control group were intraperitoneally injected with hydrocortisone on the first day of smoke exposure.The rats in the control group were placed in the same container and breathed fresh air.On the 7th,15th,and 30th days of smoke exposure,10 rats in each group were sacrificed by femoral artery exsanguination.HE staining and Masson staining were used to observe the patholog-ical changes of lung tissues in each group at each time point.The serum levels of transforming growth factor-β_(1)(TGF-β_(1)),vascular endothelial growth factor(VEGF)and tumor necrosis factor-α(TNF-α)at each time point were detected by ELI-SA.Results The results of HE staining showed that the alveolar cavity structure of the rats in the control group was nor-mal,and there was no obvious inflammation and fibrosis in the alveolar cavity.In the smoke exposure group,the alveoli at the lesion site expanded on the 7th day,and red blood cells and inflammatory cells were seen in the alveoli,accompanied by a large number of fibroblasts exudating.On the 15th day,the inflammatory cells decreased,some alveoli in the upper lobe continued to expand,and a large number of fibroblasts increased.On the 30th day,pulmonary bullae and interstitial fibrosis can be seen alternately.The pathological changes of lung tissue in thalidomide group and positive drug control group at each time point were basically the same as those in smoke exposure group,but the degree of alveolar inflamma-tion,fibrosis and pulmonary bullae were significantly reduced.Masson staining showed that a few collagen fibers were stained blue in the extracellular matrix of the right lower lung tissue of rats in the control group.In the smoke exposure group,alveolar epithelial damage and subepithelial basement membrane destruction occurred on the 7th day.Collagen fi-bers appeared in the middle and lower lungs,and a small amount of blue collagen fibers were observed.On the 15th day,the thickness of alveolar wall increased,fibrosis and a lot of scar tissue were formed,and a lot of blue-stained collagen fi-bers were seen.On the 30th day,there was little change in the upper lung bullae in comparison with the former,and a large number of alveolar wall destruction and fusion were observed in the lower lung,and a large number of dense blue col-lagen fibers were observed.Compared with the smoke exposure group,the collagen content in thalidomide group and posi-tive drug control group decreased,and the severity of pulmonary bullae decreased.Serum TGF-β_(1),VEGF,TNF-αlevels of rats in each group at the same time were as follows:smoke exposure group>positive drug control group,thalidomide group>control group(all P<0.05),and there were no significant differences in TGF-β_(1),VEGF or TNF-αlevels between thalidomide group and positive drug control group at the same time.Conclusion Thalidomide can reduce pulmonary in-terstitial fibrosis and emphysema induced by smoke exposure in rats,and its mechanism may be related to reducing inflam-matory response and inhibiting angiogenesis.