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Histopathological study on bone changes induced by recombinant granulocyte colony-stimulating factor in rats
M Suzuki1, Y Sakamaki, A Miyoshi
1Toxicology Research Laboratory, Chugai Pharmaceutical Co., Ltd., Nagano, Japan.
Summary
High doses of recombinant human granulocyte colony-stimulating factor (rG-CSF) accelerated bone resorption and osteogenesis in growing rats. The study suggests rG-CSF primarily enhances osteoclastic bone resorption during bone growth.
Area of Science:
- Bone Biology
- Pharmacology
- Histopathology
Background:
- Recombinant human granulocyte colony-stimulating factor (rG-CSF) is used to stimulate neutrophil production.
- The effects of high-dose rG-CSF on bone metabolism, particularly during growth, require further investigation.
Purpose of the Study:
- To investigate the histopathological bone changes induced by high doses of rG-CSF in growing rats.
- To determine the primary mechanism of rG-CSF's action on bone tissue during the growth phase.
Main Methods:
- Growing rats were intravenously administered high doses (100 and 1000 micrograms/kg/day) of rG-CSF for 28 days.
- Histopathological examination of bone tissues, focusing on metaphyseal spongy bone and diaphyseal compact bone.
- Analysis of osteoclastic bone resorption and osteogenesis, including intramembranous ossification.
Main Results:
- Histopathological changes were observed in areas of active bone remodeling, including metaphyseal trabeculae and endosteal regions.
- Administration of rG-CSF led to accelerated osteoclastic bone resorption and osteogenesis via intramembranous ossification.
- Osteoclastic resorption was prevalent, with approximately half of the lesions also showing accompanying osteogenesis.
Conclusions:
- rG-CSF administration in growing rats induced significant histopathological bone changes.
- The primary effect of rG-CSF on bone appears to be the acceleration of osteoclastic bone resorption.
- Intramembranous ossification-driven osteogenesis frequently accompanied the accelerated resorption, particularly at sites of high osteoclastic activity.