Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark; National Research Centre for the Working Environment, Copenhagen, Denmark.
Department of Biochemistry and Molecular Biology, Research Institute "Hospital 12 de Octubre (imas12)", Complutense University, Madrid, Spain.
Biochim Biophys Acta Biomembr. 2021 Jan 1;1863(1):183499. doi: 10.1016/j.bbamem.2020.183499. Epub 2020 Oct 31.
With the intention to move away from animal testing for the toxicological evaluation of chemicals comes the need to develop new approach methodologies which are mechanism-anchored and target relevant key events leading to an adverse outcome. To date, no validated alternative methods are available for studying the acute inhalation toxicity potential of airborne chemicals but the constrained drop surfactometer measuring the surface tension of a drop of lung surfactant presents as a promising candidate. Indeed, the correlation of the increase in minimum surface tension of lung surfactant in vitro with changes in the breathing patterns of mice after inhalation of test compounds has been shown in multiple studies. However, the causal factors leading to lung surfactant inactivation remain speculative. This paper combines molecular and biophysical methods (constrained drop and captive bubble surfactometers, Langmuir-Blodgett balance, epifluorescence microscopy, cryogenic transmission electron microscopy, and differential scanning calorimetry) applied to purified porcine lung surfactant and dipalmitoylphosphatidylcholine interfacial films to gain insights into the disruption of lung surfactant function by three chemicals known to show acute inhalation toxicity (trimethoxyoctylsilane, methyl 3-oxo-2-pentylcyclopentaneacetate, and diisopentyl ether). The results of this study suggest that the test chemicals intercalate between the phospholipids at the air-liquid interface, reduce the stability of the films, and decrease the cohesivity of interface-associated multilayered structures thereby perturbing the lung surfactant surface activity. These findings contribute to a better understanding of chemically-induced lung surfactant function disruption.
为了避免对化学物质进行动物毒性评估，需要开发新的方法，这些方法要基于机制并针对导致不良后果的相关关键事件。迄今为止，尚无经过验证的替代方法可用于研究空气中化学物质的急性吸入毒性，但受限滴落表面张力仪测量肺表面活性剂液滴的表面张力，是一种很有前途的候选方法。事实上，多项研究表明，体外肺表面活性剂最小表面张力的增加与吸入测试化合物后小鼠呼吸模式的变化之间存在相关性。然而，导致肺表面活性剂失活的因果因素仍在推测之中。本文结合了分子和生物物理方法（受限滴落和俘获气泡表面张力仪、朗缪尔-布洛杰特天平、荧光显微镜、低温传输电子显微镜和差示扫描量热法），应用于纯化的猪肺表面活性剂和二棕榈酰磷脂酰胆碱界面膜，以深入了解三种已知具有急性吸入毒性的化学物质（三乙氧基辛基硅烷、3-氧代-2-戊基环戊烷乙酸甲酯和二异戊基醚）对肺表面活性剂功能的破坏。本研究的结果表明，测试化学物质在气液界面处插入磷脂之间，降低了膜的稳定性，并降低了与界面相关的多层结构的内聚性，从而扰乱了肺表面活性剂的表面活性。这些发现有助于更好地了解化学物质引起的肺表面活性剂功能障碍。
