Effects of N-acetylcysteine and tirilazad mesylate on intestinal functional capillary density, leukocyte adherence, mesenteric plasma extravasation and cytokine levels in experimental endotoxemia in rats

Issue title: Selected Proceedings of the 14th European Conference for Clinical Hemorheology and Microcirculation, Dresden, Germany, June 27–30, 2007

Article type: Research Article

Authors: Birnbaum, J.^; | Lehmann, Ch.^; | Klotz, E. | Hein, O. Vargas | Blume, A. | Jubin, F. | Polze, N. | Luther, D. | Spies, C.D.

Affiliations: Klinik für Anästhesiologie und operative Intensivmedizin, Charité – Universitätsmedizin Berlin, Campus Charité Mitte und Campus Virchow-Klinikum, Berlin, Germany | Departments of Anesthesia, Pharmacology, Microbiology and Immunology, Dalhousie University, Victoria General Hospital, Halifax, NS, Canada

Note: [] Corresponding author: Dr. Jürgen Birnbaum, Klinik für Anästhesiologie und operative Intensivmedizin, Charité – Universitätsmedizin Berlin, Campus Charité Mitte und Campus Virchow-Klinikum, 10117 Berlin, Charitéplatz 1, Germany. Tel.: +49 030 450 531 012; Fax: +49 030 450 531 911; E-mail: [email protected].

Note: [] Jürgen Birnbaum and Christian Lehmann equally contributed to the manuscript.

Abstract: Introduction: The study's objective was to determine the effects of the administration of N-acetylcysteine (NAC) and of tirilazad mesylate (TM) on intestinal functional capillary density, mesenteric plasma extravasation, leukocyte adherence and on cytokine release during experimental endotoxemia in rats. Methods: In a prospective, randomized, controlled animal study, 80 male Wistar rats were examined in 2 test series. Both series were divided into 4 groups. Group 1 served as control group (CON group). Group 2 (LPS group), group 3 (NAC group) and group 4 (TM group) received endotoxin infusions (10 mg/kg over 2 h). In NAC group 150 mg/kg body weight NAC was administered after the first 30 minutes of endotoxemia intravenously. In TM group, 10 mg/kg body weight TM was administered after the first 30 minutes of endotoxemia intravenously. Animals of the series 1 underwent studies of leukocyte adherence on submucosal venular endothelium of the small bowel wall and intestinal functional capillary density (FCD) in the intestinal mucosa and the circular as well as the longitudinal muscle layer by intravital fluorescence microscopy (IVM). Plasma levels of interleukin 1β (IL-1β), interferone γ (IFN-γ) and soluble intercellular adhesion molecule1 (s-ICAM 1) as well as white blood cell count (WBC) were estimated. In the animals of the series 2 mesenteric plasma extravasation was determined by IVM and plasma levels of tumor necrosis factor α (TNF-α), IL-4, IL-6, IL-10 and malondialdehyde (MDA) were estimated. Results: After LPS administration, FCD in the villi intestinales was unchanged and in the longitudinal muscularis layer it was increased. There was no effect of NAC or TM administration on FCD. Although the plasma extravasation was not significantly influenced by LPS administration, TM administration resulted in a lower plasma extravasation in the TM group compared to the other groups. After endotoxin challenge, the firmly adherence of leukocytes to vascular endothelium as a parameter of leukocyte activation in endotoxemia was increased but NAC or TM administration had no influence on leukocyte adherence. The plasma levels of IL-1β, IL-6, IL-10, TNF-α, IFN-γ and sICAM-1 were increased in the endotoxemic groups (LPS group, NAC group and TM group) and the WBC was decreased compared to controls. IL-4 levels were unchanged during observation period. Plasma MDA levels were not influenced by LPS administration compared to controls. The administration of NAC resulted in lower sICAM-1 and MDA levels compared to the LPS group. The IL-1β, IL-6, IL-10, TNF-α and IFN-γ plasma levels were not influenced by NAC or TM administration. Conclusions: In this posttreatment sepsis model in rats, NAC administration resulted in lower sICAM-1 and MDA levels compared to the LPS treated animals. TM administration reduced the plasma extravasation in this model.

Keywords: Endotoxin, rat, NAC, tirilazad mesylate, intravital microscopy, intestine, mesentery, perfusion, extravasation, sepsis, cytokines

DOI: 10.3233/CH-2008-1073

Journal: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 99-111, 2008