title: Protective effect of Korean Red Ginseng against glucocorticoid-induced osteoporosis in vitro and in vivo.
abstract: BACKGROUND
  Glucocorticoids (GCs) are commonly used in many chemotherapeutic protocols and play an important role in the normal regulation of bone remodeling. However, the prolonged use of GCs results in osteoporosis, which is partially due to apoptosis of osteoblasts and osteocytes. In this study, effects of Korean Red Ginseng (KRG) on GC-treated murine osteoblastic MC3T3-E1 cells and a GC-induced osteoporosis mouse model were investigated.
  
  
  METHODS
  MC3T3-E1 cells were exposed to dexamethasone (Dex) with or without KRG and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Real-time polymerase chain reaction was performed to evaluate the apoptotic gene expression; osteogenic gene expression and alkaline phosphatase (ALP) activity were also measured. Western blotting was performed to evaluate the mitogen-activated protein kinase (MAPK) proteins. A GC-induced osteoporosis animal model was used for in vivo study.
  
  
  CONCLUSIONS
  The MTT assay revealed that Korean Red Ginseng (KRG) prevents loss of cell viability caused by Dex-induced apoptosis in MC3T3E1 cells. Real-time polymerase chain reaction data showed that groups treated with both Dex and KRG exhibited lower mRNA levels of caspase-3 and -9, whereas the mRNA levels of Bcl2, IAPs, and XIAP increased. Moreover, groups treated with both Dex and KRG demonstrated increased mRNA levels of ALP, RUNX2, and bone morphogenic proteins as well as increased ALP activity in MC3T3-E1 cells, compared to cells treated with Dex only. In addition, KRG increased protein kinase B (AKT) phosphorylation and decreased c-Jun N-terminal kinase (JNK) phosphorylation. Moreover, microcomputed tomography analysis of the femurs showed that GC implantation caused trabecular bone loss. However, a significant reduction of bone loss was observed in the KRG-treated group. These results suggest that the molecular mechanism of KRG in the GC-induced apoptosis may lead to the development of therapeutic strategies to prevent and/or delay osteoporosis.
authors.affiliation: Laboratory of Cell Differentiation Research, College of Korean Medicine, Gachon University, Seongnam, Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Kim
authors.affiliation: Laboratory of Cell Differentiation Research, College of Korean Medicine, Gachon University, Seongnam, Korea.
authors.forename: Hyejin
authors.initials: H
authors.lastname: Lee
authors.affiliation: College of Korean Medicine, Gachon University, Seongnam, Korea.
authors.forename: Ki Sung
authors.initials: KS
authors.lastname: Kang
authors.affiliation: Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon, Korea.
authors.forename: Kwang-Hoon
authors.initials: KH
authors.lastname: Chun
authors.affiliation: Laboratory of Cell Differentiation Research, College of Korean Medicine, Gachon University, Seongnam, Korea.
authors.forename: Gwi Seo
authors.initials: GS
authors.lastname: Hwang
keywords: Korean Red Ginseng; Panax ginseng; dexamethasone; osteoblast; osteoporosis