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Updated: Mar 13, 2026
Depletion and Reconstitution of Macrophages in Mice
Published on: August 1, 2012
Bone marrow-derived innate macrophages attenuate oxazolone-induced colitis
Zhao Cheng1, Hong-Ling Peng1, Rong Zhang2
1Department of Hematology, Institute of Molecular Hematology, The Second Xiang-ya Hospital, Central South University, Changsha, Hunan, PR China.
Abstract:
Previous studies have shown that a subpopulation of granulocyte macrophage colony-stimulating factor (GM-CSF)-dependent F4/80high CD11bhigh innate macrophages could be derived from bone marrow cells by continuous in vitro culturing. These cells could be induced to differentiate into M1 or M2 macrophages in vitro. In the current study, we sought to determine whether bone marrow cell-derived innate macrophages (BMIMs) could be used to fulfill an anti-inflammatory purpose by intravenous transplantation in vivo after being stimulated to differentiate into M2 macrophages. Because Th2 cytokines, such as interleukin IL-4 and IL-13, can induce macrophage polarization into M2 macrophages, we treated the BMIMs with IL-4 and IL-13 in vitro. Next, the M2 macrophages were intravenously transplanted into a typical Th2-mediated inflammatory disease model, oxazolone (OXZ)-induced colitis, to assess the anti-inflammatory activity of BMIM-derived M2 macrophages (BMIM-M2Ms) in vivo. After transplantation, the severity of intestinal inflammation was attenuated. In addition, colon lengths and mouse body weights were noticeably improved. F4/80+ CD206+ double-positive cells (displaying the markers of M2 macrophages) had accumulated in the colon tissue of BMIM-M2M-transplanted mice. This evidence demonstrated that bone marrow-derived BMIM-M2Ms could be used to alleviate OXZ-induced Th2-mediated inflammation in a mouse model in vivo.
Insights
Bone marrow-derived innate macrophages (BMIMs) differentiated into M2 macrophages can reduce inflammation. Intravenous transplantation of these M2 macrophages alleviated oxazolone-induced colitis in a mouse model.
Area of Science:
- Immunology
- Cell Biology
Background:
- Granulocyte macrophage colony-stimulating factor (GM-CSF)-dependent F4/80high CD11bhigh innate macrophages can be derived from bone marrow cells in vitro.
- These innate macrophages can be differentiated into M1 or M2 subtypes.
Purpose of the Study:
- To investigate the potential of bone marrow cell-derived innate macrophages (BMIMs) to exert anti-inflammatory effects.
- To assess the efficacy of M2-polarized BMIMs (BMIM-M2Ms) following intravenous transplantation in a mouse model of Th2-mediated inflammation.
Main Methods:
- BMIMs were cultured in vitro and polarized into M2 macrophages using Interleukin-4 (IL-4) and Interleukin-13 (IL-13).
- M2 macrophages were intravenously transplanted into mice with oxazolone (OXZ)-induced colitis.
- The therapeutic effects were evaluated by assessing inflammation severity, colon length, body weight, and M2 macrophage infiltration.
Main Results:
- Transplantation of BMIM-M2Ms significantly attenuated intestinal inflammation in the OXZ-induced colitis model.
- Improved colon lengths and mouse body weights were observed in treated mice.
- Accumulation of F4/80+ CD206+ M2 macrophages was detected in the colons of transplanted mice.
Conclusions:
- Bone marrow-derived innate macrophages, when differentiated into M2 macrophages, demonstrate significant anti-inflammatory properties in vivo.
- BMIM-M2Ms show therapeutic potential for alleviating Th2-mediated inflammatory conditions like OXZ-induced colitis.
