title: Effect of (-)-epigallocatechin-3-gallate in preventing bone loss in ovariectomized rats and possible mechanisms.
abstract: Despite recent developments reported in studies of (-)-epigallocatechin-3-gallate (EGCG), its early preventive effect of mitigating bone loss is not well understood. We investigated the effect of EGCG in preventing bone loss in ovariectomized (OVX) female rats, and explored the possible underlying mechanisms. Twelve-week-old female Sprague-Dawley rats, were divided into 3 groups: group A received intraperitoneal EGCG for 12 consecutive weeks, begun 3 days after ovariectomy; group B received ovariectomy alone; group C, received a sham operation. At the end of the experiment, tibias and femurs were harvested for: (1) micro-CT scanning and measurement of bone mineral density (BMD) and bone morphological parameters; (2) a 3-point bending test; (3) HE staining and an immunohistological study investigating Sema4D expression.
  
  
  RESULTS
  The BMD and BV/TV of group A were significantly higher than for the OVX group. The trabecular separation (Tb.Sp) of group A was significantly lower than for group B. RESULTS from the 3-point bending test showed no statistical significance among all the groups. Bone histological studies indicated that trabecular bone was denser in group C, while group B had less dense trabecular bone, and the bone morphological status of group A was intermediate between groups A and C. The immunohistological study demonstrated that Sema4D was more highly expressed as a percentage of the brown-stained area in group B than in the other 2 groups.
  
  
  CONCLUSIONS
  EGCG had a positive effect on mitigating bone loss in ovariectomized rats, and it inhibited Sema4D expression in bone tissue. Early stage supplementation of EGCG at a dose of 10 mg/kg/day after the onset of ovariectomy did not entirely eliminate bone loss.
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Song
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Minfeng
authors.initials: M
authors.lastname: Gan
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zou
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Zongping
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Shiyan
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Niu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Chenxi
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University No. 188, Shizi Street, Suzhou, Jiangsu Province, China.
authors.forename: Huilin
authors.initials: H
authors.lastname: Yang
keywords: BMD; EGCG; Sema4D; bone loss; microarchitecture; osteoporosis