Nanjaraj Urs Ankanahalli N, Yariswamy Manjunath, Ramakrishnan Chandrasekaran, Joshi Vikram, Suvilesh Kanve Nagaraj, Savitha Mysore Natarajan, Velmurugan Devadasan, Vishwanath Bannikuppe Sannanayak
Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysore, Karnataka, India.
Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, Tamil Nadu, India.
Toxicon. 2015 Jan;93:68-78. doi: 10.1016/j.toxicon.2014.11.224. Epub 2014 Nov 8.
Viperbites undeniably cause local manifestations such as hemorrhage and myotoxicity involving substantial degradation of extracellular matrix (ECM) at the site of envenomation and lead to progressive tissue damage and necrosis. The principle toxin responsible is attributed to snake venom metalloproteases (SVMPs). Treatment of such progressive tissue damage induced by SVMPs has become a challenging task for researchers and medical practitioners who are in quest of SVMPs inhibitors. In this study, we have evaluated the inhibitory potential of three specific zinc (Zn(2+)) chelating agents; N,N,N',N'-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN), diethylene triamine pentaacetic acid (DTPA), tetraethyl thiuram disulfide (TTD) on Echis carinatus venom (ECV) induced hemorrhage and myotoxicity. Amongst them, TPEN has high affinity for Zn(2+) and revealed potent inhibition of ECV metalloproteases (ECVMPs) in vitro (IC50: 6.7 μM) compared to DTPA and TTD. The specificity of TPEN towards Zn(2+) was confirmed by spectral and docking studies. Further, TPEN, DTPA, and TTD completely blocked the hemorrhagic and myotoxic activities of ECV in a dose dependent manner upon co-injection; whereas, only TPEN successfully neutralized hemorrhage and myotoxicity following independent injection. Histological examinations revealed that TPEN effectively prevents degradation of dermis and basement membrane surrounding the blood vessels in mouse skin sections. TPEN also prevents muscle necrosis and accumulation of inflammatory cells at the site of ECV injections. In conclusion, a high degree of structural and functional homology between mammalian MMPs and SVMPs suggests that specific Zn(2+) chelators currently in clinical practice could be potent first aid therapeutic agents in snakebite management, particularly for local tissue damage.
蛇咬伤无疑会引起局部表现，如出血和肌毒性，这涉及到在蛇毒注入部位细胞外基质（ECM）的大量降解，并导致组织进行性损伤和坏死。主要的致病毒素被认为是蛇毒金属蛋白酶（SVMPs）。对于寻求SVMPs抑制剂的研究人员和医学从业者来说，治疗由SVMPs引起的这种进行性组织损伤已成为一项具有挑战性的任务。在本研究中，我们评估了三种特定的锌（Zn(2+)）螯合剂；N,N,N',N'-四（2-吡啶甲基）乙二胺（TPEN）、二乙烯三胺五乙酸（DTPA）、四乙基秋兰姆二硫化物（TTD）对锯鳞蝰蛇毒（ECV）诱导的出血和肌毒性的抑制潜力。其中，TPEN对Zn(2+)具有高亲和力，与DTPA和TTD相比，在体外对ECV金属蛋白酶（ECVMPs）显示出强效抑制作用（IC50：6.7 μM）。光谱和对接研究证实了TPEN对Zn(2+)的特异性。此外，TPEN、DTPA和TTD在共同注射时以剂量依赖性方式完全阻断了ECV的出血和肌毒性活性；然而，只有TPEN在单独注射后成功中和了出血和肌毒性。组织学检查显示，TPEN有效地防止了小鼠皮肤切片中血管周围真皮和基底膜的降解。TPEN还可防止ECV注射部位的肌肉坏死和炎症细胞聚集。总之，哺乳动物基质金属蛋白酶（MMPs）和SVMPs之间高度的结构和功能同源性表明，目前临床实践中使用的特定Zn(2+)螯合剂可能是蛇咬伤治疗中有效的急救治疗药物，特别是对于局部组织损伤。
