Tularemia induces different biochemical responses in BALB/c mice and common voles

Hana Bandouchova,Jana Sedlackova,Frantisek Vitula,Ladislav Novotny,Martin Hubalek,Jiri Pikula,Miroslav Pohanka,Frantisek Treml

doi:10.1186/1471-2334-9-101

Hana Bandouchova, Jana Sedlackova + Show 6 more

Open Access

https://doi.org/10.1186/1471-2334-9-101

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Abstract

BackgroundBoth BALB/c mice and common voles (Microtus arvalis) are considered highly susceptible to tularemia. However, the common vole is reported to harbour Francisella tularensis in European habitats as well as to survive longer with chronic shedding of the bacterium. The purpose of the present study was to compare the response of these two rodents to a wild Francisella tularensis subsp. holarctica strain infection.MethodsRodents were evaluated for differences in the total antioxidant capacity derived from low-molecular-weight antioxidants, biochemistry including lipid metabolism, tissue bacterial burdens and histopathology following experimental intraperitoneal infection with 160 colony forming units (CFU) pro toto.ResultsBacterial burdens in common voles started to develop later post-exposure and amounted to lower levels than in BALB/c mice. Elevation of liver function enzymes was more pronounced in mice than common voles and there were marked differences in lipid metabolism in the course of tularemia in these two species. Hypertriglyceridemia and hypercholesterolemia developed in mice, while physiologically higher levels of triglycerides and cholesterol showed a decreasing tendency in common voles.On the other hand, the total plasma antioxidant capacity gradually dropped to 81.5% in mice on day 5 post-infection, while it increased to 130% on day 6 post-infection in common voles. Significant correlations between tissue bacterial burdens and several biochemical parameters were found.ConclusionAs differences in lipid metabolism and the total antioxidant capacity of highly susceptible rodent species were demonstrated, the role of triglycerides, cholesterol and antioxidants in tularemic sepsis should be further investigated.

Highlights

Both BALB/c mice and common voles (Microtus arvalis) are considered highly susceptible to tularemia
Natural foci of tularemia may be characterized by long-term persistence under favourable environmental conditions [3] and the F. tularensis infection has been documented in a wide range of hosts [4,5] in which it manifests in multiple forms depending on the route of exposure
For comparative purposes we evaluated differences in the total antioxidant capacity derived from the low-molecular-weight antioxidants, biochemical responses including lipid metabolism and tissue bacterial burdens

Summary

Introduction

Both BALB/c mice and common voles (Microtus arvalis) are considered highly susceptible to tularemia. Natural foci of tularemia may be characterized by long-term persistence under favourable environmental conditions [3] and the F. tularensis infection has been documented in a wide range of hosts [4,5] in which it manifests in multiple forms depending on the route of exposure. The widespread activation of cells responsive to bacteria or bacterial components generally results in the release of an array of inflammatory mediators, such as cytokines, chemokines, prostaglandins, lipid mediators, and reactive oxygen species [11]. Some studies suggest that the F. tularensis infection confers an oxidative stress upon the target cells and that many of the host-defence mechanisms appear to be intended to counteract this stress [16]. It is possible to measure the total antioxidant capacity (TAC) as a clinical marker of oxidative stress [18]

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