Solano Daniela, Rucavado Alexandra, Escalante Teresa, Tavares Edith Bastos Gandra, Bezerra Suellen Karoline Moreira, Olivo Clarice Rosa, Leick Edna Aparecida, Rojas Moscoso Julio Alejandro, Dias Lourdes, Tibério Iolanda de Fátima Lopes Calvo, Hyslop Stephen, Gutiérrez José María
Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica.
Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Rua Vital Brazil, 80, Cidade Universitária Zeferino Vaz, Campinas 13083-888, SP, Brazil.
Toxins (Basel). 2025 Jun 12;17(6):302. doi: 10.3390/toxins17060302.
An experimental model of acute pulmonary damage was developed based on the intravenous injection of the phospholipase A (PLA)-rich venom of (Papuan black snake) in mice. Venom caused pulmonary edema, with the accumulation of a protein-rich exudate, as observed histologically and by analysis of bronchoalveolar lavage fluid (BALF). In parallel, venom induced an increase in all of the pulmonary mechanical parameters evaluated, without causing major effects in terms of tracheal and bronchial reactivity. These effects were abrogated by incubating the venom with the PLA inhibitor varespladib, indicating that this hydrolytic enzyme is responsible for these alterations. The venom was cytotoxic to endothelial cells in culture, hydrolyzed phospholipids of a pulmonary surfactant, and reduced the activity of angiotensin-converting enzyme in the lungs. The pretreatment of mice with the nitric oxide synthase inhibitor L-NAME reduced the protein concentration in the BALF, whereas no effect was observed when mice were pretreated with inhibitors of cyclooxygenase (COX), tumor necrosis factor-α (TNF-α), bradykinin, or neutrophils. Based on these findings, it is proposed that the rapid pathological effect of this venom in the lungs is mediated by (a) the direct cytotoxicity of venom PLA on cells of the capillary-alveolar barrier, (b) the degradation of surfactant factor by PLA, (c) the deleterious action of nitric oxide in pulmonary tissue, and (d) the cytotoxic action of free hemoglobin that accumulates in the lungs as a consequence of venom-induced intravascular hemolysis. Our findings offer clues on the mechanisms of pathophysiological alterations induced by PLAs in a variety of pulmonary diseases, including acute respiratory distress syndrome (ARDS).
基于给小鼠静脉注射富含磷脂酶A(PLA)的巴布亚黑蛇毒液,建立了急性肺损伤实验模型。组织学观察和支气管肺泡灌洗液(BALF)分析显示,毒液导致肺水肿,并伴有富含蛋白质的渗出液积聚。同时,毒液使所有评估的肺力学参数增加,而对气管和支气管反应性无重大影响。用PLA抑制剂伐瑞拉地布孵育毒液可消除这些作用,表明这种水解酶是造成这些改变的原因。该毒液对培养的内皮细胞具有细胞毒性,可水解肺表面活性剂的磷脂,并降低肺中血管紧张素转换酶的活性。用一氧化氮合酶抑制剂L-NAME预处理小鼠可降低BALF中的蛋白质浓度,而用环氧合酶(COX)、肿瘤坏死因子-α(TNF-α)、缓激肽或中性粒细胞抑制剂预处理小鼠则未观察到效果。基于这些发现,有人提出这种毒液在肺中的快速病理作用是由以下因素介导的:(a)毒液PLA对毛细血管-肺泡屏障细胞的直接细胞毒性;(b)PLA对表面活性剂因子的降解;(c)一氧化氮在肺组织中的有害作用;(d)由于毒液诱导的血管内溶血而在肺中积聚的游离血红蛋白的细胞毒性作用。我们的研究结果为PLA在包括急性呼吸窘迫综合征(ARDS)在内的多种肺部疾病中引起的病理生理改变机制提供了线索。