Research Article The Venom of Spectacled Cobra (Elapidae: Naja naja): In Vitro Study from Distinct Geographical Origins in Sri Lanka Duminda S. B. Dissanayake , 1 Lasanthika D. Thewarage, 1 Roshitha N. Waduge, 2 J. G. S. Ranasinghe, 3 S. A. M. Kularatne, 4 and R. P. V. Jayanthe Rajapakse 1 1 Department of Veterinary Pathobiology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya, Sri Lanka 2 Department of Pathology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka 3 Department of Biochemistry, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka 4 Department of Medicine, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka Correspondence should be addressed to Duminda S. B. Dissanayake; duminda.rusl@gmail.com and R. P. V. Jayanthe Rajapakse; jayanthar@pdn.ac.lk Received 10 April 2018; Revised 18 July 2018; Accepted 11 August 2018; Published 27 September 2018 Academic Editor: Valerio Matozzo Copyright © 2018 Duminda S. B. Dissanayake et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Several countries residing envenomation due to Naja naja had revealed a disparity in the venom composition according to their geographic location and Sri Lankan cobra still lacks the evidence to support this. Terefore, the current study was focused on addressing relationship between the histopathological changes according to geographic variation of Sri Lankan N. naja venom. Te histopathological changes in vital organs and muscle tissues following intramuscular administration of venom of N. naja were studied using BALB/c mice. Te median lethal dose of venom of N. naja in the present study was determined to be 0.55, 0.66, 0.68, 0.62, and 0.7mg/kg for North (NRP), Central (CRP), Western, Southern, and Sabaragamuwa Regional Population venoms, respectively. Histopathological changes were observed in diferent levels in vital organs and muscle tissues of mice. NRP accompanied signifcantly higher infltration of infammatory and necrotic cells into skeletal muscle and CRP venom demonstrated high level of cardiotoxic efects comparing to other regions. Tis study revealed a certain extent of variations in the pathological efects of N. naja venom samples according to their geographical distribution. 1. Introduction Many tropical and subtropical countries siding with the serious medical concern of envenomation report an approx- imate annual rate of 90000 accidental human deaths due to snakebites [1–3]. Being a tropical country with diverse climatic and geographical distribution, Sri Lanka provides an excellent natural habitat for both venomous and non- venomous snakes and this contributes to demonstrating a signifcant approximate rate of 37000 snakebites cases [4, 5]. Most of the countries including Sri Lanka residing this topic of envenomation have categorized the venomous snakes responsible according to the severity of their toxicity. In this classifcation, Asian cobra is recognized as one of the highly venomous snakes. Tough the frequency of cobra bites are less than viper bites in Sri Lanka, rates of mortality and morbidity in the cases of cobra envenomation are highly notable [6]. Asian cobra including Naja naja (Figure 1) species in Sri Lanka, which taxonomically belongs to family Elapidae, is well known for its envenomation cases due to its unique haemorrhagic, hemolytic, infammatory, and necrotic efects on diferent organs leading to multiple organ failure [6]. Similar to many highly elaborated snake venom, cobra venom also comprises the major two fractions of toxic enzy- matic proteins and nonenzymatic proteins also identifed as cytotoxins [7, 8]. Hydrolytic enzymes of PLA 2 , hyaluronidase, caseinolytic AMPase, and ATPase when combined with cytotoxic neurotoxins, cobramines, membranotoxins, and cardiotoxins contribute progressively to exerting their main expected activity of immobilizing and digesting the venom Hindawi Journal of Toxicology Volume 2018, Article ID 7358472, 14 pages https://doi.org/10.1155/2018/7358472