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Updated: Aug 26, 2026
Bone Marrow-derived Macrophage Production
Published on: November 22, 2013
Megakaryocytic emperipolesis in the rat bone marrow induced by lipopolysaccharide
1Fukui Institute for Safety Research, ONO Pharmaceutical Co., Ltd., Japan.
Abstract:
Megakaryocytic emperipolesis was observed in the rat bone marrow when lipopolysaccharide (LPS) was administrated intravenously at a daily dose of 0.5 mg/kg body weight for 4 weeks. Emperipolesis was significantly increased in the LPS-treated group (3.54%) as compared with the control group (1.35%). Histologically, several types of hematocytes were engulfed within megakaryocytes, but the host cells and entering hematocytes showed no degenerative alterations. Morphologically, most megakaryocytes showing emperipolesis were classified into the mature type indicating high platelet producting ability but platelet counts in the peripheral blood were markedly reduced in the LPS-treated group (63.7 x 10(4)/mm3) as compared with the control group (128.4 x 10(4)/mm3). These results suggest that the emperipolesis is a phenomenon closely related to the marked reduction in the number of platelets and accelerated platelet production of megakaryocytes.
Insights
Lipopolysaccharide (LPS) administration in rats increased megakaryocytic emperipolesis, a process where cells engulf others. This phenomenon correlated with a significant decrease in peripheral platelet counts.
Area of Science:
- Hematology
- Cell Biology
- Immunology
Background:
- Megakaryocytes are crucial for platelet production in bone marrow.
- Emperipolesis is a poorly understood cellular interaction within the bone marrow.
- Lipopolysaccharide (LPS) is a potent immune stimulant.
Purpose of the Study:
- To investigate the effect of lipopolysaccharide (LPS) on megakaryocytic emperipolesis in rats.
- To determine the relationship between emperipolesis and platelet counts.
Main Methods:
- Rats were administered LPS intravenously (0.5 mg/kg/day) for 4 weeks.
- Bone marrow and peripheral blood were analyzed for megakaryocytes, emperipolesis, and platelet counts.
- Histological and morphological assessments were performed.
Main Results:
- LPS treatment significantly increased megakaryocytic emperipolesis from 1.35% to 3.54%.
- Hematocytes were engulfed by megakaryocytes without apparent cellular damage.
- Peripheral platelet counts were markedly reduced in LPS-treated rats (63.7 x 10^4/mm^3) compared to controls (128.4 x 10^4/mm^3).
- Megakaryocytes exhibiting emperipolesis were predominantly mature, suggesting high platelet production capacity.
Conclusions:
- LPS induces significant megakaryocytic emperipolesis in rat bone marrow.
- Emperipolesis is closely associated with a marked reduction in peripheral platelet counts.
- The findings suggest a complex interplay between emperipolesis, megakaryocyte maturation, and platelet homeostasis.
