Morphological studies in a model for dengue-2 virus infection in mice

Abstract

One of the main difficulties in studying dengue virus infection in humans and in developing a vaccine is the absence of a suitable animal model which develops the full spectrum of dengue fever, dengue haemorrhagic fever, and dengue shock syndrome. It is our proposal to present morphological aspects of an animal model which shows many similarities with the dengue infection in humans. BALB/c mice were intraperitoneally infected with non-neuroadapted dengue virus serotype 2 (DENV-2). Histopathological and morphometrical analyses of liver tissue revealed focal alterations along the infection, reaching wide-ranging portal and centrolobular veins congestion and sinusoidal cell death. Additional ultrastructural observations demonstrated multifocal endothelial injury, platelet recruitment, and alterated hepatocytes. Dengue virus antigen was detected in hepatocytes and in the capillar endothelium of the central lobular vein area. Liver function tests showed high levels of aspartate transaminase and alanine transaminase enzyme activity. Lung tissue showed interstitial pneumonia and mononuclear cells, interseptal oedema, hyperplasia, and hypertrophy of the bronchiolar epithelial cells. DENV-2 led to a transient inflammatory process, but caused focal alterations of the blood-exchange barrier. Viremia was observed from 2nd to 11th day p.i. by isolation of DENV-2 in C6/36 mosquito cell line inoculated with the supernatant of macerated liver, lung, kidney, and cerebellum tissues of the infected mice.Key words: dengue-2 virus -BALB/c mice -liver -viremia -ultrastructure -histopathology Dengue viruses (DENV) are mosquito-borne RNAviruses that are classified serologically into four antigenically distinct types (DENV-1, 2, 3, 4). They infect millions of people in tropical and subtropical regions of the world and may cause a mild to debilitating febrile illness, the classical dengue fever (DF), the dengue haemorrhagic fever (DHF), and dengue shock syndrome (DSS). However, the pathogenesis of human dengue infection (DEN) remains not sufficiently known, and no successful vaccine is available as yet (Eckels 1993). The studies on pathogenesis, pharmacodynamics, and prophylaxis of DHF have been hampered due to the lack of a suitable animal model (Bhamarapravati 1993).DENV have been inoculated into numerous species of animals by a variety of routes. Studies on laboratory mice and non-human primates remain the most wellcharacterized models (Cole & Wisseman 1969, Marchette et al. 1973, Boonpucknavig et al. 1981, Hotta et al. 1981a,b, Chaturvedi et al. 1991, Wu et al. 1995.Several studies indicated that mice are a permissive host for DENV (Meiklejhon et al. 1952, Lin et al. 1998, Johnson & Roehrig 1999. However, no infectious model that mimics DHF/DSS has yet been reported (Huang et al. 2000). Until now the great majority of mice models of DENV infection deal with suckling or young mice infected by an intracerebral route of inoculation (Nath et al. 1983, Raut et al. 1996 and with mouse-neuroadapted DENV (Desprès et al. 1998, Atrasheuskaya e...

Role of ERK1/2 signaling in dengue virus-induced liver injury

“…Balb/c mice are susceptible to DENV and provide a convenient animal model of DENV infection (Barth et al, 2006;Paes et al, 2005Paes et al, , 2009). In the present study, intravenous infection of DENV in Balb/c mice resulted in detected levels of viral RNA, viral proteins and infectious viral particles.…”

“…The result from this study and from others suggest that intravenous injection system is the good route of administration of DENV in Balb/c mice, as DENV antigens were detected, which is in contrast to the subcutaneous injection system, in which DENV antigens could not be easily detected (Franca et al, 2010). Balb/c mice have been used to study liver injury during DENV infection (Barth et al, 2006;Paes et al, 2005Paes et al, , 2009. Liver damage was more severe in the intravenous injection as compared to the intraperitoneal injection (Barth et al, 2006;Paes et al, 2005Paes et al, , 2009).…”

“…Transaminase levels are increased in DENV-infected patients (Halstead, 1988;Kuo et al, 1992;Souza et al, 2004) and in a murine model of DENV infection (Barth et al, 2006;Chen et al, 2004;Franca et al, 2010;Paes et al, 2005Paes et al, , 2009). Apoptosis of hepatic cells, which may be related to the pathogenesis of DSS, has been observed both in vitro and in vivo (Couvelard et al, 1999;El-Bacha et al, 2007;Huerre et al, 2001;Limonta et al, 2007;Lin et al, 2008;Marianneau et al, 1998;Morchang et al, 2011;Nagila et al, 2011Nagila et al, , 2013Netsawang et al, 2010;Thongtan et al, 2004).…”

Liver Dysfunctions in Dengue Infection: An Update on its Pathogenesis

“…A study from the DENV-2 infected mouse model have revealed that focal alterations in the liver along with the infection, In addition to this, ultra structural observations disclosed the alerted hepatocytes [27]. In this model dengue virus antigen was detected in the hepatocytes and thus is associated with the altered liver functions [27]. It has recently been understood that dengue infected dendritic cells activate other cells via direct contact mediated mechanism as evident that, dendritic cells activate natural killer cells via the mechanism however its mechanism of disease is not yet properly known [28].…”

“…Another important study have described that, the secreted form of dengue virus non-structural protein NS1 is engulfed by hepatocytes, that further accumulate in the endosomes showing an important mechanism for the development of dengue associated pathophysiology [14]. A study from the DENV-2 infected mouse model have revealed that focal alterations in the liver along with the infection, In addition to this, ultra structural observations disclosed the alerted hepatocytes [27]. In this model dengue virus antigen was detected in the hepatocytes and thus is associated with the altered liver functions [27].…”