title: Drynaria fortunei J. Sm. improves the bone mass of ovariectomized rats through osteocalcin-involved endochondral ossification.
abstract: OBJECTIVE
  Our previous study showed that Drynaria fortunei J. Sm. (Kunze), a traditional Chinese medical herb, can promote osteoblast differentiation and maturation. This study was further aimed to confirm the traditional effects of Kunze on the bone mass of ovariectomized rats.
  
  
  METHODS
  Female Wistar rats were given an ovariectomy and then administered the water extract of Kunze (WEK). Systemic and tissue toxicities of WEK were assessed. A biomechanical test, bone mineral contents, and bone histomorphometry were analyzed to determine the effects of the WEK on the bone mass. Levels of osteocalcin (OCN) in bone tissues were determined by immunohistochemistry and immunoblotting. The effects of naringin, one of the bioactive compounds of the WEK, on the bone mass were evaluated.
  
  
  RESULTS
  A bilateral ovariectomy in rats caused a time-dependent decrease in levels of serum 17β-estradiol. Exposure of ovariectomized rats to the WEK at 0.5 and 1g/kg body weight/day for 1, 2, 3, and 6 months did not induce systemic or tissue toxicities. Biomechanical testing and a bone mineral content analysis showed that the ovariectomy decreased the bone torsion force and bone ash in time-dependent manners. In comparison, after exposure to the WEK, the ovariectomy-induced reductions in the bone torsion force and bone ash were significantly alleviated. In parallel, results of a bone histomorphometric assay further revealed that the ovariectomy caused significant diminution in the production of prehypertrophic chondrocytes and trabecular bone but enhanced hypertrophic chondrocyte numbers in the growth plate. However, exposure to the WEK lowered ovariectomy-induced changes in these cellular events. As to the mechanism, the WEK increased OCN biosynthesis in bone tissues of ovariectomized rats. Administration of naringin to ovariectomized rats caused significant amelioration of the bone strength, bone mineral contents, and trabecular bone amounts.
  
  
  CONCLUSIONS
  This study shows that the WEK can translationally promote the bone mass in ovariectomized rats through stimulating OCN-involved endochondral ossification.
authors.affiliation: Department of Orthopedic Surgery, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan; Cell Physiology and Molecular Image Research Center, Taipei Medical University׳s Wan-Fang Hospital, Taipei, Taiwan.
authors.forename: Yong-Eng
authors.initials: YE
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Hwa-Chang
authors.initials: HC
authors.lastname: Liu
authors.affiliation: Cell Physiology and Molecular Image Research Center, Taipei Medical University׳s Wan-Fang Hospital, Taipei, Taiwan.
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Lin
authors.affiliation: Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Shing-Hwa
authors.initials: SH
authors.lastname: Liu
authors.affiliation: Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Rong-Sen
authors.initials: RS
authors.lastname: Yang
authors.affiliation: Cell Physiology and Molecular Image Research Center, Taipei Medical University׳s Wan-Fang Hospital, Taipei, Taiwan; Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan; Anesthetics Toxicology Research Center, Taipei Medical University Hospital, Taipei, Taiwan. Electronic address: rmchen@tmu.edu.tw.
authors.forename: Ruei-Ming
authors.initials: RM
authors.lastname: Chen
mesh_terms: D000818:Animals; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism; D019902:Chondrocytes / Q000378:metabolism; D005260:Female; D044950:Flavanones / Q000494:pharmacology; D008516:Medicine, Chinese Traditional; D015675:Osteocalcin / Q000187:drug effects* / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D010052:Ovariectomy; D010936:Plant Extracts / Q000494:pharmacology*; D029621:Polypodiaceae / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D044950:Flavanones; D010936:Plant Extracts; D015675:Osteocalcin; C005274:naringin
keywords: Bone mass; Drynaria fortunei J. Sm.; Endochondral ossification; Osteocalcin; Ovariectomy