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Early postmortem biochemical changes and renal immunohistochemical expression of aquaporin-2 to differentiate between saltwater and freshwater drowning: An experimental study
Manal A. Abd-ElZaher1, Shereen A. Abd-ElAleem1, Ahlam M. Abdulla2, Ahmad M. Mahmoud2, Fadia A. Mossalem3, Nashwa Gamal4
Departments of 1Forensic Medicine and Clinical Toxicology; 2Biochemistry, 3Community and 4Histology, Faculty of Medicine, El-Minia University
Abstract: Background:-Examination of immersed bodies is one of the most important aspects in forensic practice. Further differentiation is also an indispensable aspect with respect to determination of freshwater drowning (FWD) or saltwater drowning (SWD). Objective:- The present study aimed to investigate the early postmortem cardiac and vitreous biochemical changes and the immunohistochemical expression of aquaporin-2 to differentiate between salt and freshwater drowning. Methods:- The study was carried out on 30 adult male Balady rabbits weighted 1.5: 2kg. Rabbits were divided randomly into 3 groups, 10 per each group. Animals received intraperitoneal injection of pentobarbital 50ug/gm. Group(I): served as control, rabbits were sacrificed by cervical dislocation, group (II): FWD model, rabbits administered distilled water (30ml/Kg) at a rate of 1ml/min., and finally group (III): SWD model, rabbits administered (3.5%) NaCl in distilled water (30 ml/Kg) and also in the same rate. Within postmortem interval less than one hour, samples were collected as cardiac blood from right and left ventricles separately, and also the vitreous humor from right and left eyes separately. Serum and fresh incubated vitreous samples were analyzed for levels of biomarkers {K, Na, Cl, Ca, Mg, blood urea nitrogen (BUN), and vitreous urea nitrogen (VUN)}. Kidney specimens were carefully dissected and prepared for immunohistochemical expression of aquaporin-2. Results:- The most efficient markers were the high left to right ratio of BUN for hemodilution in FWD model, and the highly elevated left-right ratio of Mg, K, NA, and Cl levels in SWD model. The mixed right and left cardiac serum showed a highly significant elevated K level in FWD, meanwhile in SWD, there was there was a highly significant elevated Na, Cl, and Mg levels with reduced BUN. Vitreous humor showed highly significant elevated Na, Cl, Ca, and Mg levels in SWD and a highly significant elevated K and VUN levels in FWD. Immunohistochemical studies revealed an enhanced expression of aquaporin-2 in the apical plasma membrane of the collecting duct principle cells in SWD group compared with FWD and control groups. Conclusions: The current study suggested the usefulness of both serum and vitreous humor biochemical markers, together with the renal aquaporin-2 expression to accurately differentiate FWD from SWD in the early postmortem period. Aim of the study:- This study aimed to explore the possible early biochemical and immunohistochemical markers to differentiate between freshwater and saltwater drowning.
[Manal A. Abd-ElZaher, Shereen A. Abd-ElAleem, Ahlam M. Abdulla, Ahmad M. Mahmoud, Fadia A. Mossalem, Nashwa Gamal. Early postmortem biochemical changes and renal immunohistochemical expression of aquaporin-2 to differentiate between saltwater and freshwater drowning: An experimental study. J Am Sci2013;9(6):28-37]. (ISSN: 1545-1003). http://www.jofamericanscience.org. 4
Keywords: Drowning, cardiac biomarkers ,vitreous biomarkers, aquaporin-2. Full Text 4