Microcystin-LR (MC-LR) is a potent cyanotoxin that can reach several organs. However subacute exposure to sublethal doses of MC-LR has not yet well been studied. Herein, we evaluated the outcomes of subacute and sublethal MC-LR exposure on lungs. Male BALB/c mice were exposed to MC-LR by gavage (30 µg/kg) for 20 consecutive days, whereas CTRL mice received filtered water. Respiratory mechanics was not altered in MC-LR group, but histopathology disclosed increased collagen deposition, immunological cell infiltration, and higher percentage of collapsed alveoli. Mitochondrial function was extensively affected in MC-LR animals. Additionally, a direct in vitro titration of MC-LR revealed impaired mitochondrial function. In conclusion, MC-LR presented an intense deleterious effect on lung mitochondrial function and histology. Furthermore, MC-LR seems to exert an oligomycin-like effect in lung mitochondria. This study opens new perspectives for the understanding of the putative pulmonary initial mechanisms of damage resulting from oral MC-LR intoxication.

微囊藻毒素-LR (MC-LR) 是一种强效蓝藻毒素，可到达多个器官。然而，亚急性暴露于亚致死剂量的 MC-LR 尚未得到很好的研究。在此，我们评估了亚急性和亚致死 MC-LR 暴露对肺部的影响。雄性 BALB/c 小鼠通过管饲法 (30 µg/kg) 连续 20 天暴露于 MC-LR，而 CTRL 小鼠则接受过滤水。MC-LR 组的呼吸力学没有改变，但组织病理学显示胶原沉积增加、免疫细胞浸润和塌陷肺泡的百分比更高。线粒体功能在 MC-LR 动物中受到广泛影响。此外，MC-LR 的直接体外滴定显示线粒体功能受损。总之，MC-LR 对肺线粒体功能和组织学表现出强烈的有害影响。此外，MC-LR 似乎在肺线粒体中发挥寡霉素样作用。这项研究为理解口服 MC-LR 中毒导致的假定肺部初始损伤机制开辟了新的视角。