Immuno-phenotypic and functional characterization of rabbit pulmonary intravascular macrophages.

Abstract

Pulmonary intravascular macrophages (PIMs) are present in species such as cattle, sheep and horse and promote acute lung inflammation (ALI). Rabbits are often used as a model of ALI but there is controversy about the presence of PIMs in these species. Rabbits were treated with 10 mg/kg of gadolinium chloride intravenously (GC; n = 6) or saline (n = 6) followed by euthanasia at 48 h post-treatment to determine the presence of PIMs. In a subsequent study, rabbits were pre-treated with GC or 0.9 % saline followed by 100 μg/kg of E. coli lipopolysaccharide intravenously 48 h later. Rabbits were euthanized 24 h post-LPS treatment. Light and electron microscopy showed that PIMs attached to the capillary endothelium and were positive for RAM-11 anti-macrophage antibody. While GC treatment induced apoptotic PIMs, there was no difference in the PIM number between control and GC-treated rabbits. Rabbits administered with LPS were 3.5 times more likely to die before the end of the 24-h period than those pre-treated with GC. Lung heterophil accumulation and IL-1β, TNFα and IL-6 mRNA expression were significantly higher in rabbits administered with LPS compared to those administered with GC before the LPS injection. PIMs from the LPS-treated rabbits were positive for TNFα. Lung, BAL and serum IL-8 and MCP-1 expression was not different between LPS rabbits with or without pre-treatment with GC. We conclude that rabbit lungs contain PIMs and that their depletion reduces endotoxin-induced lung inflammation. The presence of PIMs in rabbit lungs may need to be considered while using rabbit to model acute lung injury.

• Authors: Tanya Duke-Novakovski, Sarabjeet Singh-Suri, Osamu Kajikawa, Sarah Caldwell, Chandarshekhar Charavaryamath, Baljit Singh
• Journal: Cell and tissue research (Cell Tissue Res) Vol. 351 Issue 1 Pg. 149-60 (Jan 2013) ISSN: 1432-0878 [Electronic] Germany
• PMID: 23073615 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Endotoxins
• Interleukin-1beta
• Interleukin-6
• Lipopolysaccharides
• RNA, Messenger
• Tumor Necrosis Factor-alpha
• Gadolinium
• Peroxidase
• gadolinium chloride

Topics

• Animals
• Endotoxins (toxicity)
• Gadolinium (pharmacology)
• Immunophenotyping
• Interleukin-1beta (genetics, metabolism)
• Interleukin-6 (genetics, metabolism)
• Lipopolysaccharides (pharmacology)
• Lung (blood supply, drug effects, enzymology)
• Macrophages, Alveolar (drug effects, immunology, ultrastructure)
• Peroxidase (metabolism)
• RNA, Messenger (blood, genetics)
• Rabbits
• Reverse Transcriptase Polymerase Chain Reaction
• Sputum (cytology, drug effects)
• Survival Analysis
• Tumor Necrosis Factor-alpha (genetics, metabolism)