The gastrointestinal tract is responsible for nutrient absorption, a complex task that demands an intact barrier able to let nutrients pass while shielding the host from invading microbes. To maintain and regulate intestinal homeostasis, the gut hosts one of the largest macrophage populations in the body.
By executing a unique set of seemingly contradictory duties, intestinal macrophages actively preserve GI tract homeostasis. Muscularis macrophages, for example, promote gut motility by supporting enteric neurons, whereas mucosal macrophages must simultaneously sustain oral tolerance to food antigens and eliminate pathogens that breach the epithelium. Sub-epithelial macrophages, positioned directly beneath the epithelial monolayer, are highly phagocytic and bactericidal, forming a first line of defense against invading microbes while orchestrating tissue repair and immune modulation. Vascular-associated macrophages not only block microbial entry at the mucosal level but also prevent systemic dissemination of pathogens. Thus, functionally distinct macrophage subsets reside in discrete anatomical niches—the epithelium, vascular plexus, intestinal glands, secondary lymphoid organs, muscularis externa, and enteric nervous system.
We previously described the use of clodronate liposomes to deplete pulmonary macrophages. Today we summarize publications and protocols that employ clodronate liposomes to eliminate mouse intestinal macrophages.
Literature 1
Article Source: N-Acetylglucosaminyltransferase V exacerbates murine colitis with macrophage dysfunction and enhances colitic tumorigenesis
Macrophage Clearance Methods:
Macrophage depletion protocol: 200 µL clodronate liposomes were injected i.v. via the tail vein on days 2 and 4 after DSS initiation (see the paper for DSS-induced colitis/colon cancer details).
Results are shared:
Flow-cytometric analysis showed >80 % depletion of F4/80⁺ macrophages.
Literature 2
Article Source: Macrophage depletion using clodronate liposomes decreases tumorigenesis and alters gut microbiota in the AOM/DSS mouse model of colon cancer
Macrophage depletion protocol:
8–10-week-old mice received a single i.p. dose of 10 mg kg⁻¹ azoxymethane (AOM) at week 0. DSS (MW 36–50 kDa) was given in drinking water during weeks 1 (2 %), 4 (1 %), and 7 (1 %). Starting at week 6.5, 200 µL (~1 mg) clodronate liposomes were injected i.p. twice weekly until sacrifice.
Results are shared:
qPCR for cytokines and macrophage markers showed significant reductions of F4/80 in both colon and polyp tissues (P < 0.001 and P = 0.024, respectively). MCP-1, a potent macrophage chemoattractant, was also decreased (P = 0.019).
Literature 3
Article Source: Depletion of muscularis macrophages ameliorates inflammation-driven dysmotility in murine colitis model
Macrophage depletion protocol:
Male FVB/Ant mice (100–120 days old) received 3 % DSS in drinking water for 7 days. On day 4, 200 µL clodronate liposomes were injected i.v. via the tail vein.
Results are shared:
Literature 4
Article Source: Targeting colonic macrophages improves glycemic control in high-fat diet-induced obesity
Macrophage depletion protocol:
For selective depletion of colonic macrophages, clodronate liposomes were administered intrarectally via a lubricated flexible gavage needle under anesthesia.
Results are shared:
WT mice fed a coconut-oil-based high-fat diet for 1 week received intrarectal clodronate (teal triangles) or PBS-liposomes (pink circles). a) IPGTT, body weight during IPGTT, fasting insulin, and ITT. b) Ex-vivo basal and glucose-stimulated insulin secretion from isolated islets. c) Fold-change of colonic macrophages (c-Macs) in proximal colon.
Product Recommendation
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Product name |
Item number |
Specification |
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40337ES08 |
5 mL |
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40337ES10 |
10 mL |
|
40338ES08 |
5 mL |
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|
40338ES10 |
10 mL |
|
ColitCare™ Dextran Sulfate Sodium (DSS), Colitis Grade MW: 36000~50000 |
60316ES25 |
25 g |
|
|
60316ES60 |
100 g |
|
|
60316ES76 |
500 g |
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60316ES80 |
1 kg |
We offer DSS in various molecular weights to meet diverse experimental needs. For further details, please visit the Yeasen’s website.