Quattrone S, Chiappini L, Scapagnini G, Bigazzi B, Bani D
Department Anatomy, Histology & Forensic Medicine, Section of Histology, University of Florence, Florence, Italy.
Mol Hum Reprod. 2004 May;10(5):325-30. doi: 10.1093/molehr/gah040. Epub 2004 Mar 16.
The hormone relaxin (RLX), which can be detected in human venous cord blood, has been shown to be a potent vasodilator, acting through increased expression of inducible nitric oxide synthase (NOS II) and nitric oxide (NO) generation. This study aims at clarifying whether RLX, at concentrations of 100 and 1000 ng/ml for 6 or 12 h of exposure, can influence the expression of NOS isoforms in human umbilical vein endothelial cells (HUVEC) cultured in vitro. NOS mRNA expression was studied by quantitative real-time RT-PCR, NOS protein expression and activity was studied by Western blot and nitrite assay, and immunoreactive NOS localization was performed by confocal microscopy. Untreated HUVEC expressed all the NOS isoforms, especially the constitutive, endothelial-type NOS III and, to a lesser extent, NOS II and NOS I. RLX-treated cells showed an increased expression of NOS II, attaining a maximum with 1000 ng/ml RLX, which gave rise to increased NO generation, as shown by nitrite assay. This effect of RLX appears to be mediated by activation of NOS II transcription factor NF-kappaB, since it was abolished by the NF-kappaB inhibitors curcumin-95 and dexamethasone. These findings suggest that RLX in the umbilical vein might contribute to the NO-dependent regulation of vascular tone.
在人脐静脉血中可检测到的激素松弛素（RLX），已被证明是一种强效血管舒张剂，其作用机制是通过增加诱导型一氧化氮合酶（NOS II）的表达和一氧化氮（NO）的生成。本研究旨在阐明浓度为100和1000 ng/ml的RLX在体外培养6或12小时后，是否会影响人脐静脉内皮细胞（HUVEC）中NOS亚型的表达。通过定量实时RT-PCR研究NOS mRNA表达，通过蛋白质印迹法和亚硝酸盐测定研究NOS蛋白表达和活性，并通过共聚焦显微镜进行免疫反应性NOS定位。未经处理的HUVEC表达所有NOS亚型，尤其是组成型内皮型NOS III，其次是NOS II和NOS I。经RLX处理的细胞显示NOS II表达增加，在1000 ng/ml RLX时达到最大值，亚硝酸盐测定表明这导致NO生成增加。RLX的这种作用似乎是由NOS II转录因子NF-κB的激活介导的，因为NF-κB抑制剂姜黄素-95和地塞米松可消除这种作用。这些发现表明，脐静脉中的RLX可能有助于NO依赖性的血管张力调节。
