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Protective effect of <i>Rhizoma drynariae</i> extract on osteoporosis in ovariectomized rat model


Yu-li Cai
Xing-cai Zhang

Abstract

Purpose: To investigate the therapeutic effect of Rhizoma Drynariae extract (RDE) on ovariectomyinduced osteoporosis in rats.
Methods: Female Sprague-Dawley rats were randomly assigned to a sham-operated group (control) and five ovariectomy (OVX) subgroups: OVX with vehicle (OVX), OVX with 17ß-estradiol (E2, 25 μg/kg/day), and OVX with RDE doses (40, 80, and 160 mg/kg/day). Daily oral administration of E2 or RDE started 4 weeks after OVX and lasted for 16 weeks. The bone mineral density (BMD) of the L4 vertebrae and right femurs was estimated. The length of each femur was measured with a  micrometer gauge, and the center of the diaphysis determined. Three   representatives L4 vertebrae were selected to evaluate the trabecular  microarchitecture. Serum alkaline phosphatase (ALP), urinary calcium (U-Ca),
urinary phosphorus (U-P), urinary creatinine (Cr) and osteocalcin (OC) levels were measured.
Results: The study showed that high-dose of RDE significantly inhibited the bone mineral density (BMD) reduction of L4 vertebrae (0.20 ± 0.02 g/cm3, p < 0.05) and femurs (0.18 ± 0.02 g/cm3, p < 0.05) caused by OVX and prevented the  deterioration of trabecular microarchitecture (p < 0.05), which were accompanied by a significant decrease in skeletal remodeling (p < 0.05) as evidenced by the lower
levels of bone turnover markers. High-dose of RDE improved morphometric parameters, namely, Tb-N (3.8 ± 0.2 mm, p < 0.05), Tb-Th (0.083 ± 0.011 mm, p < 0.05) and Tb-Sp (0.19 ± 0.01 mm, p < 0.05) in L4 vertebrae significantly. The present study indicates that the administration of RDE at higher doses over a  16-week period can prevent OVX-induced osteoporosis in rats without hyperplastic effects on the uterus.
Conclusion: Thus, RDE is a potential natural alternative for postmenopausal  osteoporosis treatment in elderly women.


Keywords: Rhizoma Drynariae, Postmenopausal osteoporosis, Ovariectomy, Bone mineral density, Morphometric


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eISSN: 1596-9827
print ISSN: 1596-5996