Osteoprotective effect of Monascus-fermented dioscorea in ovariectomized rat model of postmenopausal osteoporosis.
This experiment established the ovariectomized (OVX) rat model of postmenopausal osteoporosis and examined the effect of the oral administration of different dosages of dioscorea, red mold dioscorea (RMD), and soy isoflavones on bone mineral density (BMD). Three months after osteoporosis had been induced and 4 weeks after feeding had begun, the tibia and femur BMD of OVX rats administered RMD showed significant increases compared with that of all other groups of OVX rats. Closer examination using microcomputed tomography also revealed that the RMD-administered rats had denser trabecular bone volume and a higher trabecular number compared to all other rat groups. Reconstructed 3D imaging indicated increases in cancellous bone mineral content, cancellous bone mineral density, and cortical bone mineral content of the proximal tibia in OVX rats. These findings indicate that administration of monacolin K and phytoestrogen diosgenin could prevent bone loss induced by estrogen deficiency.
Chiang SS, Chang SP, Pan TM
J. Agric. Food Chem. Sep 2011
Diosgenin stimulates osteogenic activity by increasing bone matrix protein synthesis and bone-specific transcription factor Runx2 in osteoblastic MC3T3-E1 cells.
Diosgenin, a steroid saponin extracted from the root of wild yam (Dioscorea villossa) is claimed to have osteogenic property. However, detailed studies providing evidence to this claim have not been fully undertaken. In this study, we investigated the effect of diosgenin on the osteogenesis of murine MC3T3-E1 osteoblastic cells. Cells were cultured with varying levels of diosgenin (0-10 μM) within 25 days of bone formation period. Diosgenin was found to stimulate proliferation within the range of 0.01-5 μM using MTT assay. The medium and cellular levels of Type 1 collagen and alkaline phosphatase (ALP), both of which are major bone matrix proteins, increased within the low range of diosgenin concentration (>0-3 μM), and this pattern was further confirmed by collagen and ALP staining of the extracellular matrix (ECM). The cellular protein expression of ALP and collagen Type 1 was also increased at 0.1-1 μM diosgenin treatment as analyzed by Western blot. Calcium deposition within the ECM also showed the same pattern as assessed by Alizarin Red S and Von Kossa staining. Bone-specific transcription factor runt-related transcription factor 2 (Runx2) and Runx2-regulated osteopontin protein expressions were induced at low concentration (0.1-1 μM) and again decreased with high diosgenin concentrations. Based on our findings, our study suggests that diosgenin can enhance bone formation by stimulating the synthesis and secretion of Type 1 collagen and ALP and bone marker proteins Runx2 and osteopontin expression. The increased levels of these marker proteins, in turn, can increase the formation of calcium deposits within the ECM thereby increasing bone formation.
Alcantara EH, Shin MY, Sohn HY, Park YM…
J. Nutr. Biochem. Nov 2011
Diosgenin induces hypoxia-inducible factor-1 activation and angiogenesis through estrogen receptor-related phosphatidylinositol 3-kinase/Akt and p38 mitogen-activated protein kinase pathways in osteoblasts.
Diosgenin, extracted from the root of wild yam (Dioscorea villosa), has been reported to demonstrate an opportunity for medical application. Vascular endothelial growth factor-A (VEGF-A) plays an important role in bone-related angiogenesis, a critical process occurring during bone formation and fracture healing. In this study, we examine whether diosgenin is able to induce VEGF-A expression and to promote angiogenesis in osteoblasts. For murine MC3T3-E1 preosteoblast-like cells, VEGF-A mRNA and protein expression seemed to be significantly elevated in response to diosgenin in a concentration-dependent fashion. Conditioned media prepared from cells treated with diosgenin induced strong angiogenic activity in either in vitro or ex vivo angiogenesis assay. Furthermore, diosgenin treatment increased the stability and activity of HIF-1alpha protein. Inhibition of HIF-1alpha activity by transfection with DN-HIF-1alpha significantly diminished diosgenin-mediated VEGF-A up-regulation. The use of pharmacological inhibitors or genetic inhibition revealed that both the phosphatidylinositol 3-kinase (PI3K)/Akt and p38 signaling pathways were potentially required for diosgenin-induced HIF-1 activation and subsequent VEGF-A up-regulation. It is noteworthy that an estrogen receptor binding assay revealed that diosgenin has the strong ability to replace [(3)H]estradiol bound to estrogen receptor (IC(50), 10 nM). In addition, the specific estrogen receptor antagonists ICI 182,780 (faslodex) and tamoxifen were noted to be able to strongly inhibit diosgenin-induced, src kinase-dependent Akt and p38 MAPK activation. Taken together, such results provide evidence that diosgenin up-regulates VEGF-A and promotes angiogenesis in preosteoblast-like cells by a hypoxia-inducible factor-1alpha-dependent mechanism involving the activation of src kinase, p38 MAPK, and Akt signaling pathways via estrogen receptor.
Yen ML, Su JL, Chien CL, Tseng KW…
Mol. Pharmacol. Oct 2005
PMID: 15998873 | Free Full Text
The use of estrogen, DHEA, and diosgenin in a sustained delivery setting as a novel treatment approach for osteoporosis in the ovariectomized adult rat model.
It is well established that the pattern of bone loss from the cortex in osteoporotic bone begins from the endosteal surface of the cortex, where there is enlargement of the medullary canal at the expense of the inner cortex. Bone loss does not occur at the periosteal surface. The objective of the following study was to induce osteoporosis in female rats by ovariectomy, followed by treatment with sustained delivery of Diosgenin (DG), dehydroepiandrosterone (DHEA), or estrogen (E) after clinical signs of osteoporosis. Female Sprague Dawley rats were divided randomly into five groups containing four rats/group. Rats comprising group 1 were left intact and served as a control group. Animals in groups 2-5 were ovariectomized (OVX) and, after a 14 day delay to allow for induction of osteoporosis, were implanted with TCPL capsules containing DG, DHEA, and E, respectively. The experiment was ceased after 33 days of treatment, at which time the vital and reproductive organs for each group were collected, weighed, and analyzed histomorphometrically for differences. Further analysis of the progression of osteoporosis in the experimental animals was obtained by performing x-ray analysis of each group on a semi-weekly basis. By collecting and analyzing the femurs from each animal, we were also able to obtain important information about the histologic changes associated with osteoporosis (left femur), as well as data regarding the effects of osteoporosis on the mechanical strength of bone via three point bending analysis (right femur). The data generated by this study revealed important information as to the efficacy and safety of the alternative treatments DHEA, E, and DG for osteoporosis. First, histomorphometric analysis revealed that treatment with DHEA, E, and DG reduced the endosteal perimeter and cortical area to values very similar to controls (intact). Second, results of the bending stress and modulus in OVX and treated animals were not statistically different from the intact control animals, which suggests that the material properties of the bone were unaltered. Third, there is an increase in total body weight associated with OVX that is reduced to control levels after replacement therapy. Finally, OVX also resulted in reproductive tissue atrophy, which was reversed by all three of the treatment regimens in this study. These data suggest that bone loss after OVX can be significantly reduced by supplementation with sustained levels of DHEA, E, and DG without jeopardizing other body organs.
Higdon K, Scott A, Tucci M, Benghuzzi H…
Biomed Sci Instrum 2001