权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A breakthrough in paraquat-induced pulmonary fibrosis

百草枯诱导的肺纤维化研究取得突破

基本信息

批准号：
10670405
负责人：
TOMITA Masafumi
金额：
$ 0.83万
依托单位：
KAWASAKI MEDICAL SCHOOL
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

First, we studied the effect of nitric oxide (NO) and glutathione (GSH) levels on PQ toxicity in A549 cells and rat organs exposed to PQ.Our in vitro models demonstrated that NO showed both beneficial and deleterious actions, depending on the concentrations produced and model system used. We detected, in vivo models, a remarkable increase in iNOS mRNA level and deposit of nitrotyrosine in liver tissues, whereas gene expressions for cytokines increased in lung tissues, suggesting that the mechanisms of PQ poisoning are different among organs exposed to PQ.We found a specific increase in GSH levels, the activities and the expression levels of the rate-limiting enzymes in GSH synthesis ; γ-glutamylcysteine synthetase (γ-GCS) and γ-glutamyl transpeptidase (γ-GT) in lungs exposed to PQ.Also, the GSH levels in A549 cells slightly increased by incubation with PQ.Next, by analyzing cholesterol-derived hydroperoxide, we found 7 α-OOH and 7 β-OOH accumulations in rat liver and kidney exposed to low dose of PQ, especially they reflected greater oxidative stress in the pathology of kidney. Finally, to identify genes that are differentially expressed in response to oxidative stress due to PQ, we carried out RT-PCR based differential display experiments using cDNAs from rat lungs that were treated for 3 hrs with 20 mg/kg PQ.Numerous cDNA bands were identified that were up-regulated and down-regulated ; a few clone were homologous to known genes and the remainders were unknown. Unknown six different cDNA clones were isolated and sequenced. The differential mRNA expression of these clones could be verified using RT-PCR method. These results may prove useful in elucidating the molecular changes during pulmonary fibrosis evoked by PQ intake.

首先，我们研究了一氧化氮(NO)和谷胱甘肽(GSH)水平对PQ对A549细胞和大鼠器官毒性的影响。我们的体外模型表明，NO既有有益的作用，也有有害的作用，具体取决于所产生的浓度和所使用的模型系统。在活体模型中，我们检测到肝组织中iNOS mRNA水平和硝基酪氨酸沉积显著增加，而肺组织中细胞因子的基因表达增加，这表明PQ中毒的机制在不同器官中是不同的。肺组织中γ-谷氨酰半胱氨酸合成酶(γ-GCS)和γ-谷氨酰转肽酶(γ-GT)的含量也略有升高。其次，通过对胆固醇衍生的过氧化氢的分析，我们发现低剂量的PQ在大鼠肝和肾脏中分别积累了7个α-OHO和7个β-OHO，特别是反映了肾脏病理中更大的氧化应激。最后，为了找出PQ引起的氧化应激反应中差异表达的基因，我们用20 mg/kg的PQ处理大鼠肺3h，进行了基于RT-PCR的差异显示实验，发现了大量上调和下调的cDNA带；少数克隆与已知基因同源，其余的未知。对未知的6个不同的克隆进行了分离和测序。用RT-PCR方法验证了这些克隆的差异表达。这些结果可能有助于阐明PQ摄入引起的肺纤维化过程中的分子变化。