Apoptosis and expression of Fas/Fas ligand mRNA in bleomycin-induced pulmonary fibrosis in mice
Apoptosis and expression of Fas/Fas ligand mRNA in bleomycin-induced pulmonary fibrosis in mice
复制标题
DOI：
10.1165/ajrcmb.16.1.8998084
复制
发表时间：
1997-01-01
影响因子：
6.4
通讯作者：
Hara, N
中科院分区：
文献类型：
--
作者：
Hagimoto, N;Kuwano, K;Hara, N
检测博来霉素诱导的小鼠肺纤维化中细胞凋亡的发生率以及Fas抗原（Fas）/Fas配体（FasL）mRNA的表达。雄性ICR小鼠气管内滴注博莱霉素（5U/kg体重）。对照组注射无菌盐水。在博来霉素滴注后1、6和12小时以及1、3、5、7、9和14天麻醉并处死动物。我们通过琼脂糖凝胶电泳上的DNA片段化、末端脱氧核苷酸转移酶介导的dUTP生物素缺口末端标记以及电镜来评估肺组织中细胞凋亡的发生率，并通过逆转录聚合酶链反应（RT-PCR）检测Fas和FasL mRNA的表达。通过原位杂交分析Fas mRNA的定位，并通过RT原位PCR分析FasL mRNA的定位。结果显示，（1）单次滴注博莱霉素会导致支气管和肺泡上皮细胞迅速出现凋亡，并在1天内消退；（2）在滴注博来霉素后第7天细胞凋亡再次出现并持续14天以上。这伴随着纤维化的进展。皮质类固醇给药完全阻止细胞凋亡和纤维化。博莱霉素滴注可上调肺泡上皮细胞中 Fas mRNA 的表达。博来霉素处理后浸润淋巴细胞中的 FasL mRNA 也上调，但在对照小鼠中则不然。皮质类固醇的施用抑制了 Fas 和 FasL mRNA 的表达以及细胞凋亡和纤维化。尽管这些结果并未表明Fas/FasL系统介导的细胞凋亡与博莱霉素诱导的纤维化直接相关，但我们推测过度细胞凋亡和Fas/FasL系统在博莱霉素诱导的肺损伤的发病机制中发挥作用。
The incidence of apoptosis and the expression of Fas antigen (Fas)/Fas ligand (FasL) mRNA in bleomycin-induced pulmonary fibrosis in mice were examined. Male ICR mice were intratracheally instilled with bleomycin (5 U/kg of body weight). The controls were injected with sterile saline. The animals were anesthetized and killed at 1, 6, and 12 h, and 1, 3, 5, 7, 9, and 14 days after bleomycin instillation. We assessed the incidence of apoptosis in lung tissues by DNA fragmentation on agarose gel electrophoresis, terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling, and electron microscopy, The expression of Fas and FasL mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). The localization of Fas mRNA was analyzed by in situ hybridization and that of FasL mRNA was analyzed by RT in situ PCR. The results showed that (1) a single instillation of bleomycin leads to the rapid appearance of apoptosis in bronchial and alveolar epithelial cells, which resolves within 1 day, and (2) apoptosis reappears on day 7 and continues for over 14 days after bleomycin instillation. This was accompanied with a progression of fibrosis. Corticosteroid administration completely blocked both apoptosis and fibrosis. The expression of Fas mRNA was upregulated in the alveolar epithelial cells by the bleomycin instillation. FasL mRNA was also upregulated in infiltrating lymphocytes after bleomycin treatment, but not in the control mice, The administration of corticosteroids suppressed the expression of Fas and FasL mRNA as well as apoptosis and fibrosis. Although these results do not show that apoptosis mediated by the Fas/FasL system is directly linked to bleomycin-induced fibrosis, we speculate that excessive apoptosis and the Fas/FasL system play a role in the pathogenesis of bleomycin-induced lung injury.