Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
Toxins (Basel). 2024 Sep 19;16(9):405. doi: 10.3390/toxins16090405.
The widespread geographical distribution of Russell's vipers ( spp.) is associated with marked variations in the clinical outcomes of envenoming by species from different countries. This is likely to be due to differences in the quantity and potency of key toxins and, potentially, the presence or absence of some toxins in venoms across the geographical spectrum. In this study, we aimed to isolate and pharmacologically characterise the major neurotoxic components of venoms from Thailand and Java (Indonesia) and explore the efficacy of antivenom and a PLA inhibitor, Varespladib, against the neuromuscular activity. These data will provide insights into the link between venom components and likely clinical outcomes, as well as potential treatment strategies. Venoms were fractionated using RP-HPLC and the in vitro activity of isolated toxins assessed using the chick biventer cervicis nerve-muscle preparation. Two major PLA fractions (i.e., fractions 8 and 10) were isolated from each venom. Fraction 8 from both venoms produced pre-synaptic neurotoxicity and myotoxicity, whereas fraction 10 from both venoms was weakly neurotoxic. The removal of the two fractions from each venom abolished the in vitro neurotoxicity, and partially abolished myotoxicity, of the whole venom. A combination of the two fractions from each venom produced neurotoxic activity that was equivalent to the respective whole venom (10 µg/mL), but the myotoxic effects were not additive. The in vitro neurotoxicity of fraction 8 (100 nM) from each venom was prevented by the pre-administration of Thai Russell's viper monovalent antivenom (2× recommended concentration) or preincubation with Varespladib (100 nM). Additionally, the neurotoxicity produced by a combination of the two fractions was partially reversed by the addition of Varespladib (100-300 nM) 60 min after the fractions. The present study demonstrates that the in vitro skeletal muscle effects of Thai and Javanese venoms are primarily due to key PLA toxins in each venom.
罗素蝰蛇（ spp.）广泛分布，其毒液导致的中毒临床表现因种属来源的不同而存在显著差异。这可能是由于不同国家的蛇种毒液中关键毒素的含量和效力存在差异，以及毒液中某些毒素的存在或缺失所致。在这项研究中，我们旨在分离并药理学鉴定来自泰国和爪哇（印度尼西亚）的蛇毒中的主要神经毒性成分，并探索抗蛇毒血清和 PLA 抑制剂 Varespladib 对神经肌肉活动的疗效。这些数据将为了解毒液成分与可能的临床结果之间的关系提供依据，并为潜在的治疗策略提供参考。我们使用反相高效液相色谱（RP-HPLC）对毒液进行分级，并用鸡双腹肌神经-肌肉标本评估分离毒素的体外活性。从每种毒液中均分离出两种主要的 PLA 级分（即 8 级分和 10 级分）。两种毒液的 8 级分均产生突触前神经毒性和肌毒性，而两种毒液的 10 级分均仅有微弱的神经毒性。从每种毒液中去除这两个级分，可消除整个毒液的体外神经毒性，并部分消除其肌毒性。两种毒液的两个级分混合物产生的神经毒性活性与各自的全毒液（10 µg/mL）相当，但肌毒性作用不具有加和性。100 nM 来自每种毒液的 8 级分的体外神经毒性可通过预先给予泰国罗素蝰蛇单价抗蛇毒血清（推荐浓度的 2 倍）或与 Varespladib 预孵育来预防。此外，在两个级分混合物产生的神经毒性 60 分钟后加入 Varespladib（100-300 nM）可部分逆转其毒性。本研究表明，泰国和爪哇蛇毒的体外骨骼肌效应主要归因于每种毒液中的关键 PLA 毒素。
