Department of Functional Sciences, Faculty of veterinary Medicine, Pharmacology and Toxicology, Fundamental and Applied Research for Animals & Health (FARAH), University of Liège, 4000 Liege, Belgium.
Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada.
Molecules. 2024 Oct 19;29(20):4954. doi: 10.3390/molecules29204954.
Hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG) are protoxins produced by plants, particularly , and are responsible for causing atypical myopathy (AM) in equids. These protoxins metabolise into toxic compounds, such as methylenecyclopropylacetyl-CoA (MCPA-CoA), which alters energy metabolism and induces severe rhabdomyolysis. Currently, no specific treatment exists for this poisoning, in vitro models fail to reproduce HGA's toxic effects on equine primary myoblasts, and mammalian models are impractical for large-scale drug screening. This study aimed to develop a zebrafish embryo model for screening therapeutic compounds against AM. Zebrafish embryos were exposed to various concentrations of HGA, MCPrG, and methylenecyclopropylacetate (MCPA) for 72 h. MCPrG did not induce toxicity, while HGA and MCPA showed median lethal concentration (LC50) values of 1.7 µM and 1 µM after 72 h, respectively. The highest levels of the conjugated metabolite MCPA-carnitine were detected 24 h after HGA exposure, and the acylcarnitines profile was highly increased 48 h post-exposure. Isovaleryl-/2- methylbutyrylcarnitine levels notably rose after 24 h, suggesting potential exposition biomarkers. Glycine and carnitine effectively reduced mortality, whereas riboflavin showed no protective effect. These findings suggest that the zebrafish embryo represents a valuable model for identifying therapeutic compounds for poisoning.
低血糖素 A (HGA) 和亚甲基环丙基甘氨酸 (MCPrG) 是植物产生的前体毒素，特别是在豆科植物中，导致马属动物非典型肌病 (AM)。这些前体毒素代谢成有毒化合物，如亚甲基环丙基乙酰辅酶 A (MCPA-CoA)，改变能量代谢并诱导严重的横纹肌溶解。目前，这种中毒没有特定的治疗方法，体外模型无法复制 HGA 对马原代成肌细胞的毒性作用，而哺乳动物模型不适合大规模药物筛选。本研究旨在开发一种斑马鱼胚胎模型，用于筛选治疗 AM 的治疗化合物。将斑马鱼胚胎暴露于不同浓度的 HGA、MCPrG 和亚甲基环丙基乙酸酯 (MCPA) 中 72 小时。MCPrG 没有引起毒性，而 HGA 和 MCPA 在 72 小时后分别显示出 1.7µM 和 1µM 的半数致死浓度 (LC50) 值。HGA 暴露后 24 小时检测到最高水平的共轭代谢物 MCPA-肉碱，暴露后 48 小时酰基肉碱谱显著增加。异戊酰基-/2-甲基丁酰肉碱水平在 24 小时后明显升高，提示可能有暴露生物标志物。甘氨酸和肉碱有效降低死亡率，而核黄素没有保护作用。这些发现表明，斑马鱼胚胎是鉴定治疗 AM 中毒的治疗化合物的有价值模型。
