Zymosan-Induced Peritonitis
Materials Required
Principle
Zymosan-induced peritonitis is a sterile acute-inflammation model produced by intraperitoneal injection of zymosan, a yeast cell-wall particle preparation, followed by quantification of leukocyte recruitment and soluble inflammatory mediators in peritoneal lavage fluid[1]. Low-dose zymosan peritonitis is commonly used as a self-resolving acute inflammation model in which neutrophil recruitment occurs early and monocyte/macrophage accumulation follows later[1][2][3].
The assay readouts include total peritoneal leukocyte number, differential neutrophil and monocyte/macrophage counts, peritoneal cytokines and chemokines, plasma or peritoneal exudation, and optional lipidomic or metabolomic changes during inflammation and resolution[1][2][3][4][5]. Early neutrophil recruitment after zymosan depends strongly on complement and mast-cell C5a receptor signaling, whereas later monocyte recruitment is linked to MCP-1/CCL2 production[2][3][6].
MCE has not independently verified the accuracy of these methods. They are for reference only.
Experimental Materials
Reagents and chemicals
• Use zymosan A suspended in sterile PBS or saline for intraperitoneal induction of peritonitis[1][4][5].• Published mouse studies used zymosan doses ranging from 0.1 mg per mouse for lower-intensity inflammatory profiling to 1 mg per mouse for classic leukocyte-recruitment and resolution studies, while some intervention studies used higher sublethal dosing such as 500 mg/kg[1][3][4][5][7].
Antibodies, probes, dyes, or kits
• Use flow-cytometry antibodies or cytology stains to identify peritoneal neutrophils and monocytes/macrophages; published studies used GR1 and CD11b to identify neutrophils, CD11b-positive macrophage populations, and F4/80 to identify monocyte/macrophage accumulation[3][6][8].• Use ELISA, multiplex bead assays, or validated mediator assays to measure cytokines and chemokines such as TNF-α, IL-1β, IL-6, IL-10, KC/CXCL1, MCP-1/CCL2, and MIP-1α[4][5][6][8].
Equipment and instruments
• Required equipment includes animal injection supplies, sterile lavage syringes and needles, tubes for peritoneal lavage fluid, a hemocytometer or automated cell counter, cytospin and microscope or flow cytometer for differential leukocyte analysis, and ELISA or multiplex-analysis equipment for mediator measurement[1][3][4][6].• LC-MS or metabolomics/lipidomics instrumentation is optional when the endpoint is resolution-associated metabolic or sphingolipid profiling[5][9].
Experimental Procedure
Preparation Steps
• Use age-, sex-, and strain-matched mice and assign animals to at least vehicle-control and zymosan-treated groups[1][4][5].• Prepare zymosan suspension freshly or according to the cited laboratory method, maintain the same zymosan lot, dose, vehicle volume, and injection route across all groups, and include PBS or saline injection controls[1][4][5].
• Select endpoint timing before beginning the experiment because early peritoneal neutrophilia has been measured at 4 h, monocyte/macrophage accumulation has been assessed at 16–24 h, and resolution studies have followed leukocyte decline from 24–72 h or longer depending on zymosan dose[1][3][5].
• Use multiple time points when the study question concerns recruitment kinetics or inflammatory resolution rather than a single acute endpoint[1][3][5].
Operation Steps
• Step 1: Inject zymosan intraperitoneally at the literature-supported dose selected for the study design[1][4][5].• Step 2: For a standard acute leukocyte-recruitment model, use 1 mg zymosan per mouse and collect lavage at early and late time points, because MCP-1 production was maximal at 4 h and F4/80-positive monocyte accumulation was maximal between 16 and 24 h after 1 mg zymosan injection[3].
• Step 3: For lower-intensity lipidomic profiling, use 0.1 mg zymosan per mouse and collect peritoneal fluid, peritoneal cells, plasma, and spleen at 2, 4, 8, and 16 h as reported in a murine sphingolipid study[9].
• Step 4: At the planned endpoint, euthanize mice according to institutional animal-use approval and lavage the peritoneal cavity with a fixed volume of buffer; published IL-27 experiments used 5 mL PBS for peritoneal flushing 12 h after zymosan injection[6].
• Step 5: Count total lavage cells and identify leukocyte subsets by cytology or flow cytometry[1][3][6].
• Step 6: Separate lavage supernatant from cells and measure inflammatory mediators such as TNF-α, IL-1β, IL-6, IL-10, KC/CXCL1, MCP-1/CCL2, and MIP-1α when those endpoints are required[4][5][6].
• Step 7: If plasma leakage is an endpoint, quantify exudation using the same method across all animals, because zymosan peritonitis studies have used plasma exudation as an inflammatory readout[4][7].
• Step 8: If resolution is the endpoint, compare leukocyte numbers across serial time points because low-dose zymosan inflammation resolves between 24 and 48 h, whereas higher-dose zymosan can persist longer before returning toward control levels[5].
Data Acquisition and Analysis
• Analyze total peritoneal cells together with differential neutrophil and monocyte/macrophage counts, because zymosan peritonitis changes both the magnitude and composition of the peritoneal leukocyte population over time[1][3][5][6].• Interpret early 4–12 h responses mainly as acute neutrophil recruitment and later 16–24 h responses as monocyte/macrophage-associated recruitment or transition, while recognizing that exact kinetics depend on dose and model design[1][3][5][6].
• Use vehicle-injected mice as negative controls and zymosan-injected mice as positive inflammatory controls[1][4][5].
• Report mouse strain, sex, age, zymosan source and dose, vehicle, injection volume, endpoint time, lavage volume, cell-counting method, leukocyte-subset markers, mediator assay, biological replicate number, and statistical test[1][4][5][6].
Troubleshooting
Problem: Neutrophil recruitment is lower than expected at the early endpoint.
• Possible Cause: Early zymosan-induced neutrophilia is strongly dependent on complement and mast-cell C5a receptor signaling, and the response can vary with biological context or pathway disruption.• Literature-supported Solution: Confirm the 4–12 h endpoint, verify the zymosan dose and route, and interpret reduced neutrophilia in relation to complement, C5aR, mast-cell, or chemokine-pathway effects when these variables are present[2][6].
Problem: Monocyte/macrophage recruitment is weak at 16–24 h.
• Possible Cause: MCP-1/CCL2 is a major mediator of monocyte recruitment in zymosan peritonitis.• Literature-supported Solution: Measure MCP-1/CCL2 in lavage fluid and include F4/80 or equivalent monocyte/macrophage markers when evaluating late-cell recruitment[3][8].
Problem: Inflammation does not resolve within the expected 24–48 h window.
• Possible Cause: Zymosan dose changes the inflammatory time course, with higher-dose zymosan producing more persistent leukocyte accumulation.• Literature-supported Solution: Use low-dose zymosan for self-resolving inflammation studies and include serial time points when comparing resolution kinetics[5].
Problem: Cytokine changes do not match cell-recruitment changes.
• Possible Cause: Some interventions alter chemokines more strongly than cytokines, as IL-27 reduced KC, MCP-1, and MIP-1α in peritoneal fluid without broadly reducing cytokine levels in the cited model.• Literature-supported Solution: Measure both leukocyte counts and chemokines rather than relying only on cytokines as the inflammatory endpoint[6].
References:
- [1]. Cash JL, et al. Chapter 17. Zymosan-induced peritonitis as a simple experimental system for the study of inflammation. Methods Enzymol. 2009;461:379-396. [Content Brief]
- [2]. Mullaly SC, et al. Mast cell-expressed complement receptor, not TLR2, is the main detector of zymosan in peritonitis. Eur J Immunol. 2007;37(1):224-234. [Content Brief]
- [3]. Ajuebor MN, et al. Endogenous monocyte chemoattractant protein-1 recruits monocytes in the zymosan peritonitis model. J Leukoc Biol. 1998;63(1):108-116. [Content Brief]
- [4]. Leite JA, et al. Ouabain modulates zymosan-induced peritonitis in mice. Mediators Inflamm. 2015;2015:265798. [Content Brief]
- [5]. Fujieda Y, et al. Inflammation and resolution are associated with upregulation of fatty acid β-oxidation in Zymosan-induced peritonitis. PLoS One. 2013;8(6):e66270. [Content Brief]
- [6]. Watzlawick R, et al. Anti-inflammatory effects of IL-27 in zymosan-induced peritonitis: inhibition of neutrophil recruitment partially explained by impaired mobilization from bone marrow and reduced chemokine levels. PLoS One. 2015;10(9):e0137651. [Content Brief]
- [7]. Bellavita R, et al. Temporin L-derived peptide as a regulator of the acute inflammatory response in zymosan-induced peritonitis. Biomed Pharmacother. 2020;123:109788. [Content Brief]
- [8]. Takahashi M, et al. Monocyte chemoattractant protein-1 (MCP-1), not MCP-3, is the primary chemokine required for monocyte recruitment in mouse peritonitis induced with thioglycollate or zymosan A. J Immunol. 2009;183(5):3463-3471. [Content Brief]
- [9]. Pierron A, et al. Zymosan-induced murine peritonitis is associated with an increased sphingolipid synthesis without changing the long to very long chain ceramide ratio. Int J Mol Sci. 2023;24(3):2773. [Content Brief]
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