肺间质纤维化前胶原和肿瘤坏死因子α基因表达

Gene expression of messenger RNA coding for procollagen and tumour necrosis factor α in lungs undergoing bleomycin induced pulmonary fibrosis.

目的探讨博莱霉素致大鼠肺间质纤维化肺组织前胶原Ⅰ、前胶原Ⅲ及肿瘤坏死性因子α（ＴＮＦα）ｍＲＮＡ表达的变化及意义。方法３０只大鼠随机分为：（１）正常对照组５只，经气管内一次性灌注生理盐水；（２）灌注博莱霉素分为博莱霉素３、７、１４、２１、３０天组，每组各５只。灌注博莱霉素后，分别在相应的时间点取肺组织，提取总ＲＮＡ，用ＲＮＡ吸印杂交（Ｎｏｒｔｈｅｒｎ杂交）和斑点杂交测定肺组织的ＴＮＦα、前胶原Ⅰ，前胶原Ⅲ的ｍＲＮＡ。结果灌注博莱霉素３和７天组肺组织的ＴＮＦαｍＲＮＡ的表达与正常对照组比较，ｔ值分别为１０．３３、１２．５４（Ｐ＜０．０１）；博莱霉素７天组前胶原Ⅰ、前胶原Ⅲ的ｍＲＮＡ开始表达，与正常对照组比较ｔ值分别为１０．５６、２４．２３（Ｐ＜０．０１）；１４天组达到峰值水平；博莱霉素３０天组的前胶原ⅠｍＲＮＡ与正常对照组比较ｔ值为１６．６７（Ｐ＜０．０１）；而前胶原Ⅲ的ｍＲＮＡ水平与正常对照组比较ｔ值为１．９５（Ｐ＞０．０５）。Ｎｏｒｔｈｅｒｎ杂交显示，前胶原Ⅰ、前胶原Ⅲ的ｍＲＮＡ均有两个转录模板。结论（１）博莱霉素致肺间质纤维化时，前胶原Ⅰ和前胶原Ⅲ基因表达增加，胶原基因转录水平的升高，引起的胶原?

Objective mRNA for tumour necrosis factor α(TNF α) and procollagen Ⅰ [pro α1(Ⅰ)] and Ⅲ(pro α1(Ⅲ)was measured in bleomycin treated mice to evaluate their roles in pulmonary fibrosis .Method 30 male Wistar mice were divided into normal control group and groups treated by bleomycin on days 3,7,14,21,30.Each group included 5 mice, and the mice were treated by single intratracheal instillation with sterile saline solution or with 5 mg /kg body weight of bleomycin. The mice were sacrificed at different days , and total RNA from the lungs of bleomycin or saline solution instilled mice was extracted. Expression of TNF α, pro α1 (I) and pro α1(Ⅲ)mRNA was measured by dot blot and Northern blot hybridization. Result The levels of TNF α mRNA in lungs of bleomycin groups on days 3,7 were significantly higher than those of control group ( t =10.33 and 12.54 respectively ; P <0.01). The levels of pro α1 (I) and pro α1(Ⅲ)mRNA in lungs of bleomycin group on day 7 were higher than those of control group( t =10.56 and 24.23 respectively ; P <0.01), After reaching the peak levels in two weeks, the levels of pro α1(Ⅲ) mRNA in lungs of bleomycin group on day 30 declined slowly to approximately the values of normal control group ( t =1.95; P >0.05); but the levels of pro α1(Ⅰ) mRAN on day 30 after bleomycin administration were higher than those of control group ( t =16.67; P <0.01). The mRNA coding pro α1(Ⅰ) and pro α1(Ⅲ) in lungs of mice had two mRNA species.Conclusion The results suggested that the metabolism of mRNAs for pro α 1 (Ⅰ) and pro α 1 (Ⅲ) may be preferentially perturbed, and that increase of collagen gene expression in the transcriptional level might be involved in the mechanism of collagen accumulation. The increased expression of TNF α gene may play an important role in the early events of bleomycin induced pulmonary fibrosis.