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United States Department of Agriculture

Agricultural Research Service

Research Project: BONE METABOLISM IN OBESITY Title: Supplementation with green tea polyphenols improves bone microstructure and quality in aged, orchidectomized rats

Authors
item Shen, Chwan-Li -
item Cao, Jay
item Dagda, Raul -
item Tenner, Thomas -
item Chyu, Ming-Chien -
item Yeh, James -

Submitted to: Calcified Tissue International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 25, 2011
Publication Date: March 23, 2011
Repository URL: http://handle.nal.usda.gov/10113/58159
Citation: Shen, C., Cao, J.J., Dagda, R.Y., Tenner, T.E., Chyu, M., Yeh, J.K. 2011. Supplementation of green tea polyphenols improves bone microstructure and quality in aged, orchidectomized rats. Calcified Tissue International. 88(6):455-463.

Interpretive Summary: We evaluated whether green tea polyphenols (green tea bioactive components) can improve bone structural parameters in aged orchidectomized rats with low serum testosterone levels. We found that orchidectomy decreased liver glutathione peroxidase activity, bone mineral density, and bone strength. Orchidectomy also decreased trabecular bone volume, number and thickness in distal femur and proximal tibia, and bone formation rate in trabecular bone of proximal tibia. Supplementation of green tea phlyphenols increased bone mineral density, and trabecular volume, number, and strength of femur, increased trabecular volume and thickness, and bone formation in both proximal tibia and periosteal tibial shaft, decreased eroded surface in proximal tibia and endocortical tibial shaft, and increased liver glutathione peroxidase activity. We concluded that green tea polyphenols GTP supplementation attenuates trabecular and cortical bone loss through increasing bone formation while suppressing bone resorption due to its antioxidant capacity. Our data show that consumption of green tea polyphenols improved bone microstructure and quality in aged male animals with low bone mass.

Technical Abstract: Recent studies show that green tea polyphenols (GTP) attenuate bone loss and microstructure deterioration in ovariectomized aged female rats, a model of postmenopausal osteoporosis. However, it is not known if such an osteo-protective role of GTP is demonstrable in androgen-deficient aged rats, a model of male osteoporosis. We evaluated the efficacy of GTP in mitigation of bone loss and microstructure deterioration along with related mechanism in aged male rats. A 2 (sham vs. orchidectomy) × 2 (no GTP and 0.5% GTP in drinking water) factorial design was studied for 20 weeks using 40 aged male rats. An additional 10 rats (baseline group) were euthanized at the beginning of study to provide baseline parameters. There was no difference in femoral mineral density between baseline and the sham only group. Orchidectomy suppressed serum testosterone concentration, liver glutathione peroxidase activity, bone mineral density, and bone strength. Orchidectomy also decreased trabecular bone volume, number and thickness in distal femur and proximal tibia, and bone formation rate in trabecular bone of proximal tibia, but increased bone formation rates in endocortical tibial shaft. GTP supplementation resulted in increased bone mineral density, and trabecular volume, number, and strength of femur, increased trabecular volume and thickness, and bone formation in both proximal tibia and periosteal tibial shaft, decreased eroded surface in proximal tibia and endocortical tibial shaft, and increased liver glutathione peroxidase activity. We concluded that GTP supplementation attenuates trabecular and cortical bone loss through increasing bone formation while suppressing bone resorption due to its antioxidant capacity.

Last Modified: 9/21/2014
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