The effects of Rhizoma Curculiginis and Rhizoma Drynariae extracts on bones

BACKGROUND: Rhizoma Curculiginis (Xianmao) and Rhizoma Drynariae (Gusuibu) are 'Yang-tonifying' traditional Chinese herbal medicines used to strengthen bones. This investigation aims to assess the systemic effect of extracts of Rhizoma Curculiginis and Rhizoma Drynariae on bone histomorphology and formation, and their local effect on bone healing. METHODS: For the investigation of the systemic effect, thirty 8-week-old male BALB/c mice were divided into three groups: (1) control group, ten mice fed daily with distilled water; (2) Rhizoma Curculiginis group, ten mice fed daily with distilled water mixed with Rhizoma Curculiginis extract; (3) Rhizoma Drynarie group, ten mice fed daily with distilled water mixed with Rhizoma Drynarie extract. The mice were fed for five weeks before sacrifice. Twenty micro-tomographic slices with an increment of 0.25 mm were prepared to cover the proximal end of the left tibia of each mouse. Quantitative morphometry of the bone structure was performed. For the investigation of the local effect on bone healing, two bone defects (5 × 10 mm) were created in the parietal bone of each of the three New Zealand white rabbits. Two defects in the first animal were grafted with collagen matrix with Rhizoma Curculiginis extract; two defects in the second animal were grafted with collagen matrix with Rhizoma Drynarie extract; two defects in the third (control) animal were grafted with collagen matrix alone. The animals were sacrificed on day 14 and the defects were dissected and prepared for histological and ultrastructural assessment. RESULTS: Rhizoma Curculiginis and Rhizoma Drynariae extracts altered the bone histomorphology, both increasing the trabecular number by 10% (P = 0.002). Rhizoma Curculiginis extract increased bone density by 3.13% (P = 0.122) and Rhizoma Drynariae extract increased bone density by 6.45% (P = 0.005). Both Rhizoma Curculiginis and Rhizoma Drynariae extracts induced new bone formation on the margins of the defects. CONCLUSION: Two 'Yang-tonifying' herbs, Rhizoma Curculiginis and Rhizoma Drynariae, were demonstrated to have systemic effects on bone histomorphology and formation as well as local bone healing.