Research

A remission spectroscopy system for in vivo monitoring of hemoglobin oxygen saturation in murine hepatic sinusoids, in early systemic inflammation

Christian Wunder¹ , Robert W Brock³ , Alfons Krug² , Norbert Roewer¹ and Otto Eichelbrönner¹

¹  Klinik und Poliklinik für Anästhesiologie, Julius-Maximilians-Universität Würzburg, Zentrum für Operative Medizin, Oberdürrbacher Strasse 6, 97080 Würzburg, Germany

²  LEA Medizintechnik GmbH, 35394 Giessen, Germany

³  Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 72205-7199 Little Rock, USA

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Comparative Hepatology 2005, 4:1doi:10.1186/1476-5926-4-1

Published:	12 January 2005

Abstract

Background

During the early stages of systemic inflammation, the liver integrity is compromised by microcirculatory disturbances and subsequent hepatocellular injury. Little is known about the relationship between the hemoglobin oxygen saturation (HbsO₂) in sinusoids and the hepatocellular mitochondrial redox state, in early systemic inflammation. In a murine model of early systemic inflammation, we have explored the association between the sinusoidal HbsO₂ detected with a remission spectroscopy system and 1.) the NAD(P)H autofluorescence (an indicator of the intracellular mitochondrial redox state) and 2.) the markers of hepatocellular injury.

Results

Animals submitted to 1 hour bilateral hindlimb ischemia (I) and 3 hours of reperfusion (R) (3.0 h I/R) exhibited lower HbsO₂ values when compared with sham. Six hours I/R (1 hour bilateral hindlimb ischemia and 6 hours of reperfusion) and the continuous infusion of endothelin-1 (ET-1) further aggravated the hypoxia in HbsO₂. The detected NAD(P)H autofluorescence correlated with the detected HbsO₂ values and showed the same developing. Three hours I/R resulted in elevated NAD(P)H autofluorescence compared with sham animals. Animals after 6.0 h I/R and continuous infusion of ET-1 revealed higher NAD(P)H autofluorescence compared with 3.0 h I/R animals. Overall the analysed HbsO₂ values correlated with all markers of hepatocellular injury.

Conclusion

During the early stages of systemic inflammation, there is a significant decrease in hepatic sinusoidal HbsO₂. In parallel, we detected an increasing NAD(P)H autofluorescence representing an intracellular inadequate oxygen supply. Both changes are accompanied by increasing markers of liver cell injury. Therefore, remission spectroscopy in combination with NAD(P)H autofluorescence provides information on the oxygen distribution, the metabolic state and the mitochondrial redox potential, within the mouse liver.