Comprehensive comparison of three different animal models for systemic inflammation.

BACKGROUND: To mimic systemic inflammation in humans, different animal models have been developed. Since these models are still discussed controversially, we aimed to comparatively evaluate the most widely used models with respect to the systemic effects, the influence on organ functions and to the underlying pathophysiological processes. METHODS: Systemic inflammation was induced in C57BL/6N mice with lipopolysaccharide (LPS) treatment, peritoneal contamination and infection (PCI), or cecal ligation and puncture (CLP). Blood glucose and circulating cytokine levels were evaluated at 0, 2, 4, 6, 12, 24, 48, and 72 h after induction of inflammation. Additionally, oxidative stress in various organs and liver biotransformation capacity were determined. Markers for oxidative stress, apoptosis, infiltrating immune cells, as well as cytokine expression patterns, were assessed in liver and spleen tissue by immunohistochemistry. RESULTS: Treating mice with LPS and PCI induced a very similar course of inflammation; however, LPS treatment elicited a stronger response. In both models, serum pro-inflammatory cytokine levels rapidly increased whereas blood glucose decreased. Organs showed early signs of oxidative stress, and apoptosis was increased in splenic cells. In addition, liver biotransformation capacity was reduced and there was pronounced immune cell infiltration in both the liver and spleen. Mice exposed to either LPS or PCI recovered after 72 h. In contrast, CLP treatment induced comparatively fewer effects, but a more protracted course of inflammation. CONCLUSIONS: The LPS model of systemic inflammation revealed to be most suitable when being interested in the impact of new therapies for acute inflammation. When using the CLP model to mimic human sepsis more closely, a longer time course should be employed, as the treatment induces delayed development of systemic inflammation.

Administration of AMD3100 in endotoxemia is associated with pro-inflammatory, pro-oxidative, and pro-apoptotic effects in vivo.

BACKGROUND: Chemokine receptor 4 (CXCR4) is a multifunctional G protein-coupled receptor that is activated by its natural ligand, C-X-C motif chemokine 12 (CXCL12). As a likely member of the lipopolysaccharide (LPS)-sensing complex, CXCR4 is involved in pro-inflammatory cytokine production and exhibits substantial chemo-attractive activity for various inflammatory cells. Here, we aimed to characterize the effects of CXCR4 blockade in systemic inflammation and to evaluate its impact on organ function. Furthermore, we investigated whether CXCR4 blockade exerts deleterious effects, thereby substantiating previous studies showing a beneficial outcome after treatment with CXCR4 agonists in endotoxemia. METHODS: The CXCR4 antagonist AMD3100 was administered intraperitoneally to mice shortly after LPS treatment. After 24 h, health status was determined and serum tumor necrosis factor alpha (TNF alpha), interferon gamma (IFN gamma), and nitric oxide (NO) levels were measured. We further assessed oxidative stress in the brain, kidney, and liver as well as liver biotransformation capacity. Finally, we utilized immunohistochemistry and immunoblotting in liver and spleen tissue to determine cluster of differentiation 3 (CD3), CD8, CD68, and TNF alpha expression patterns, and to assess the presence of various markers for apoptosis and oxidative stress. RESULTS: Mice treated with AMD3100 displayed impaired health status and showed enhanced serum levels of TNF alpha, IFN gamma and NO levels in endotoxemia. This compound also amplified LPS-induced oxidative stress in all tissues investigated and decreased liver biotransformation capacity in co-treated animals. Co-treatment with AMD3100 further inhibited expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf-2), heme oxygenase-1 (HO-1), and various cytochrome P450 enzymes, whereas it enhanced expression of CD3, inducible nitric oxide synthase, and TNF alpha, as well as the total number of neutrophils in liver tissue. Spleens from co-treated animals contained large numbers of erythrocytes and neutrophils, but fewer CD3+ cells, and demonstrated increased apoptosis in the white pulp. CONCLUSIONS: AMD3100 administration in a mouse model of endotoxemia further impaired health status and liver function and mediated pro-inflammatory, pro-oxidative, and pro-apoptotic effects. This suggests that interruption of the CXCR4/CXCL12 axis is deleterious in acute inflammation and confirms previous findings showing beneficial effects of CXCR4 agonists in endotoxemia, thereby more clearly elucidating the role of CXCR4 in inflammation.

Protective Effect of Casperome®, an Orally Bioavailable Frankincense Extract, on Lipopolysaccharide- Induced Systemic Inflammation in Mice.

Introduction: Despite recent advances in critical care, sepsis remains a crucial cause of morbidity and mortality in intensive care units. Therefore, the identification of new therapeutic strategies is of great importance. Since ancient times, frankincense is used in traditional medicine for the treatment of chronic inflammatory disorders such as rheumatoid arthritis. Thus, the present study intends to evaluate if Casperome® (Casp), an orally bioavailable soy lecithin-based formulation of standardized frankincense extract, is able to ameliorate systemic effects and organ damages induced by severe systemic inflammation using a murine model of sepsis, i.e., intraperitoneal administration of lipopolysaccharides (LPS). Methods: Male 60-day-old mice were assigned to six treatment groups: (1) control, (2) LPS, (3) soy lecithin (blank lecithin without frankincense extract), (4) Casp, (5) soy lecithin plus LPS, or (6) Casp plus LPS. Soy lecithin and Casp were given 3 h prior to LPS treatment; 24 h after LPS administration, animals were sacrificed and health status and serum cytokine levels were evaluated. Additionally, parameters representing liver damage or liver function and indicating oxidative stress in different organs were determined. Furthermore, markers for apoptosis and immune cell redistribution were assessed by immunohistochemistry in liver and spleen. Results: LPS treatment caused a decrease in body temperature, blood glucose levels, liver glycogen content, and biotransformation capacity along with an increase in serum cytokine levels and oxidative stress in various organs. Additionally, apoptotic processes were increased in spleen besides a pronounced immune cell infiltration in both liver and spleen. Pretreatment with Casp significantly improved health status, blood glucose values, and body temperature of the animals, while serum levels of pro-inflammatory cytokines and oxidative stress in all organs tested were significantly diminished. Finally, apoptotic processes in spleen, liver glycogen loss, and immune cell infiltration in liver and spleen were distinctly reduced. Casp also appears to induce various cytochromeP450 isoforms, thus causing re-establishment of liver biotransformation capacity in LPS-treated mice. Conclusion: Casp displayed anti-inflammatory, anti-oxidative, and hepatoprotective effects. Thus, orally bioavailable frankincense extracts may serve as a new supportive treatment option in acute systemic inflammation and accompanied liver dysfunction.

Administration of a CXCL12 Analog in Endotoxemia Is Associated with Anti-Inflammatory, Anti-Oxidative and Cytoprotective Effects In Vivo.

BACKGROUND: The chemokine receptor CXCR4 is a multifunctional receptor which is activated by its natural ligand C-X-C motif chemokine 12 (CXCL12). As CXCR4 is part of the lipopolysaccharide sensing complex and CXCL12 analogs are not well characterized in inflammation, we aimed to uncover the systemic effects of a CXCL12 analog in severe systemic inflammation and to evaluate its impact on endotoxin induced organ damages by using a sublethal LPS dose. METHODS: The plasma stable CXCL12 analog CTCE-0214D was synthesized and administered subcutaneously shortly before LPS treatment. After 24 hours, mice were sacrificed and blood was obtained for TNF alpha, IFN gamma and blood glucose evaluation. Oxidative stress in the liver and spleen was assessed and liver biotransformation capacity was determined. Finally, CXCR4, CXCL12 and TLR4 expression patterns in liver, spleen and thymus tissue as well as the presence of different markers for apoptosis and oxidative stress were determined by means of immunohistochemistry. RESULTS: CTCE-0214D distinctly reduced the LPS mediated effects on TNF alpha, IFN gamma, ALAT and blood glucose levels. It attenuated oxidative stress in the liver and spleen tissue and enhanced liver biotransformation capacity unambiguously. Furthermore, in all three organs investigated, CTCE-0214D diminished the LPS induced expression of CXCR4, CXCL12, TLR4, NF-κB, cleaved caspase-3 and gp91 phox, whereas heme oxygenase 1 expression and activity was induced above average. Additionally, TUNEL staining revealed anti-apoptotic effects of CTCE-0214D. CONCLUSIONS: In summary, CTCE-0214D displayed anti-inflammatory, anti-oxidative and cytoprotective features. It attenuated reactive oxygen species, induced heme oxygenase 1 activity and mitigated apoptosis. Thus, the CXCR4/CXCL12 axis seems to be a promising target in the treatment of acute systemic inflammation, especially when accompanied by a hepatic dysfunction and an excessive production of free radicals.