The fruit of Chaenomeles sinensis (Thouin) Koehne (Chaenomelis Fructus) known as “Mo-Gua” in Korea has been commonly used in traditional medicine to treat inflammatory diseases, such as sore throat. However, its effect on bone metabolism has not been elucidated yet. Here, we examined the effect of Chaenomelis Fructus ethanol extract (CFE) on receptor activator of nuclear factor (NF)-κB ligand (RANKL)-mediated osteoclast differentiation and formation. CF-E considerably inhibited osteoclast differentiation and tartrate-resistant acid phosphatase-positive multinuclear cell formation from bone marrow-derived macrophages and osteoclast precursor cells in a dose-dependent manner. In addition, the formation of actin rings and resorption pits were significantly suppressed in CF-E-treated osteoclasts as compared with the findings in non-treated control cells. Consistent with these phenotypic inhibitory results, the expressions of osteoclast differentiation marker genes (Acp5, Atp6v0d2 , Oscar, CtsK, and Tm7sf4) and Nfatc1 , a pivotal transcription factor for osteoclastogenesis, were markedly decreased by CF-E treatment. The inhibitory effect of CF-E on RANKL-induced osteoclastogenesis was associated with the suppression of NFATc1 expression, not by regulation of mitogen-activated protein kinases and NF-κB activation but by the inactivation of phospholipase C gamma 1 and 2. These results indicate that CF-E has an inhibitory effect on osteoclast differentiation and formation, and they suggest the possibility of CF-E as a traditional therapeutic agent against bone-resorptive diseases, such as osteoporosis, rheumatoid arthritis, and periodontitis.

Introduction
Materials and Methods
    1. 실험 배지 및 시약
    2. 모과 에탄올 추출물 준비
    3. 세포독성 평가
    4. 파골세포 분화, actin ring 및 absorption pit 형성 측정
    5. RNA 분리 및 실시간 정량 real-time polymerase chainreaction (PCR) 분석
    6. Western blot analysis
    7. 통계분석
Results
    1. 파골세포 전구세포(BMMs)에 대한 모과 에탄올 추출물(CF-E)의 세포독성(cytotoxicity)
    2. 모과 에탄올 추출물(CF-E)의 파골세포 분화(differentiation), 생성(formation) 및 뼈흡수 활성(bone resorption activity)에서의 효과
    3. 모과 에탄올 추출물(CF-E)의 파골세포 분화인자(differentiation factors) 발현에서의 효과
    4. 모과 에탄올 추출물(CF-E)의 RANKL-유도 파골세포 분화및 생성 억제 신호전달 기전
Discussion
References

• Geun Ha Park(Department of Oral Microbiology and Immunology, Wonkwang University College of Dentistry)
• Dong Ryun Gu(Department of Oral Microbiology and Immunology, Wonkwang University College of Dentistry)
• Seoung Hoon Lee(Department of Oral Microbiology and Immunology, Wonkwang University College of Dentistry/Institute of Biomaterial and Implant, Wonkwang University College of Dentistry) Correspondence to