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Bone microarchitecture in hip fracture patients — An application of non-invasive high-resolution peripheral quantitative computed tomography (HR-pQCT)
Abstracts / Bone 47 (2010) S385–S458
178 Effect of hepcidin on proliferation, apoptosis, mineralization and gene expression of osteoblast (hFOB1.19) in vitro Yong Ma, YiuJia Xu The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China Objective: In recent years, the relationship between iron metabolism and bone metabolism has had many developments and hepcidin has been known as a small peptide hormone that functions as a homeostatic regulator of iron metabolism. To research relationship between iron metabolism and bone metabolism, hepcidin and osteoblast were selected as research objects. In this research, we investigate effect of hepcidin on proliferation, apoptosis, mineralization and influence on COLI, BGP and OPG gene expression of osteoblast (hFOB1.19) in vitro, providing research data about iron related bone metabolism. Methods: After hFOB1.19 osteoblasts were cultured in vitro, we treated the cells with hepcidin (0 nmol/L, 100 nmol/L and 200 nmol/L) for 24 h and 48 h. MTT assay was used to detect each hole that absorb light OD value in enzymelinked immunosorbent detector at 490 nm which represented cell proliferation viability. When the cells, induced by serum-free hunger, were added with hepcidin for 48 h, we detected the influence of hepcidin on osteoblast apoptosis by using Annexin intervention V/PI staining and flow cytometry. We intervened in osteoblasts with hepcidin for 15 days and observed calcium nodules by von Kossa staining assay. We counted the number of calcium nodules to investigate effect of hepcidin on cell mineralization. At the same time, when the cells were treated with hepcidin for 72 h, we detected gene expression of COLI, BGP and OPG by RT-PCR. Results: The OD value indicating cell proliferation viability had no difference in different groups at 24 h and 48 h. As compared to the control, apoptosis rate of cells added with hepcidin were lower. Osteoblasts apoptosis rate dropped from the control group 7.32% to 100 nmol/L 4.99% and 200 nmol 2.46%. Data acquisition in twodimensional scatterplot chart showed that apoptotic cell numbers were fewer in hepcidin groups and effect on anti-apoptosis in 200 nmol/L was stronger than that of 100 nmol/L. There were significant differences as compared to the control group. The numbers of calcium nodules of cells treated with hepcidin were more than the controls and they had significant differences. The number increase of calcium nodules is the most obvious in 200 nmol/L. Intervention of hepcidin in hFOB1.19 cells culture, as compared with the control group, the relative content of COL1, OPG, BGP mRNA boost. In this experiment, osteogenesis-related gene expression raise positive with hepcidin concentration increase. There were significant differences in hepcidin (100 nmol/L, 200 nmol/L, 400 nmol/L) as compared with the control group. Although there was an increase, there was no significant difference in 50 nmol/L concentration. Conclusion: Hepcidin can decrease rate of apoptosis and enhance the calcium nodules of osteoblast 1.19, although hepcidin had no effect on cell proliferation viability. Hepcidin protected osteoblasts by reduce rate of apoptosis and promoted the formation of mineralization by increasing calcium nodules. In this study, hepcidin, which was an important hormone in iron metabolism can increase COL1, OPG, BGP gene expression of hFOB1.19, might promote osteoblast function, participating in the bone metabolism process. Based on our research of the influences on osteoblasts (hFOB1.19) metabolism, hepcidin regulation might be an important intervention spot on iron metabolism and bone metabolism.
doi:10.1016/j.bone.2010.09.198
S407
179 Clinical features and SQSTM1 gene mutation filter of sporadic and familial cases of Paget's disease of bone Jie-mei Gu, Zhen-lin Zhang The Department of Osteoporosis, Metabolic Bone Disease and Genetic Research Unit, Shanghai JiaoTong University Affiliated Sixth People's Hospital, Shanghai, China Objective: To improve our knowledge of diagnosis and treatment of Paget's disease of bone (PDB), and find possible pathogenic gene, we analyzed clinical features and did SQSTM1 gene mutation filter of 12 sporadic cases and 3 familial cases of PDB. Methods: Twelve sporadic cases and 3 cases of a PDB family were diagnosed and the clinical manifestation, X-ray character, change of the biochemical marker of bone turnover and the treatment of diphosphonates were all employed. And on all the cases we performed a SQSTM1 gene mutation filter. Results: Sporadic cases: 1) 8 males and 4 females, average age 63.7 ± 14.8 years. 2) The average course of disease was 5.0 ± 3.8 years. It was clinically manifested by the pain and deformity of the bone involved. 3) Bone lesions of 5 patients were limited to a single site, while others had multiple bone lesions. The most common sites were pelvis, femurs and tibia; the second most common sites were spine and skull. 4) X-ray imaging showed impaired trabecular bone structure of disordered, enlargement and deformation of the skull; tubular bones had cortical thickening, expansion or enlargement; in the spine, an involved vertebral body is typically enlarged and a picture frame effect may occur due to cortical thickening of the vertebral bodies. 5) Nine of the patients had radionuclide bone scans. The typical appearance was one of markedly increased tracer uptake in the affected bones. 6) Serum alkaline phosphatase (ALP) was detected in all patients before therapy, from 93 u/L to 1366 u/L (median 323 u/L). Nine patients were treated with diphosphonates, and their ALP was significantly decreased. 7) All the patients had SQSTM1 gene mutation filter, only a 53-year-old man had gene mutation. Familial case: We obtained a Chinese pedigree with PDB in 45 members of 3 generations. Three patients were diagnosed, including two men and one woman. The three patients were all in the second generation. The average course of disease was 3.3 ± 2.3 years. The three cases all had concealment onset, gradually difficulty in walking and were weak in the legs. They also felt an ache in their backs. Typical appearance in plain radiography and radionuclide bone scans were found in these cases. ALP was high in case 1 and case 3, and decreased after treatment. The three cases all received diphosphonates to reduce the pain. We didn't find SQSTM1gene mutation in these three cases. Conclusion: PDB is rare in China. The important diagnostic evidence is the remarkable change of biochemical marker of bone turnover and the typical radiological display. Diphosphonates in the vein is effective on Paget's disease of bone. It was the first time to report SQSTM1 gene mutation of sporadic cases of PBD in Chinese Han ethnic people. There may be other gene mutation in familial cases that needs to be further researched.
doi:10.1016/j.bone.2010.09.199
180 Bone microarchitecture in hip fracture patients — An application of non-invasive high-resolution peripheral quantitative computed tomography (HR-pQCT) Vivian Hung, Elaine Tsz-ning Fong, Wing-hoi Cheung, Kwok-sui Leung, Ling Qin The Chinese University of Hong Kong, Hong Kong, China Objective: Hip fracture is the commonest type of osteoporotic fractures. The aim of this study is to use high-resolution peripheral
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Abstracts / Bone 47 (2010) S385–S458
quantitative computed tomography (HR-pQCT) to evaluate the bone quality profile of subjects with and without non-traumatic hip fracture non-invasively. Methods: Hip fractured postmenopausal women (n = 25) and age- and gender-matched normal controls (n = 38) were recruited. The bone quality at the non-dominant distal radius and non-fracture (fracture group)/non-dominant (control group) of distal tibia were measured by HR-pQCT (XtremeCT, Scanco Medical AG). HR-pQCT, with 82 mm resolution, provided volumetric trabecular BMD (Dtrab), cortical BMD (Dcort), bone to tissue volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp). Independent t-test was used for between-group analysis. Results: Similar age and body weight were found in both groups. At the distal tibia, all vBMDs, including total BMD, Dtrab and Dcort, were significantly lower in the hip fracture (HF) group (−26.2 to −7.5%; all, p < 0.02). For bone microarchitecture parameters, lower BV/TV (−21.2%; p = 0.02) and higher Tb.Sp (+56.4%; p = 0.02), were found in the HF group. Moreover, the HF group had significantly smaller cortical bone area (−30.5%; p < 0.01) and cortical thickness (−32.5%; p < 0.01), while bone area in the trabecular region was significantly larger (+ 14.5%; p = 0.02) as compared with the control group. Similar findings were also found at the distal radius. Discussion and conclusion: Lower vBMDs and poor bone microarchitecture at both distal tibia and radius were found in the hip fracture group as compared with those of the control. In addition to BMD, our results suggested that poor bone microarchitecture was associated with hip fracture. Of all the parameters, trabecular separation was more sensitive in detecting patient with hip fracture. Smaller cortical bone area and cortical thickness together with larger trabecular bone area are typical structural deterioration in osteoporotic patients with significant trabecularization or osteoporosis of cortical bone. Our HR-pQCT findings may imply cortical thinning was also observed in hip fracture group. Bone structural information and BMD, measured by non-invasive HR-pQCT with low radiation, help us understand the characteristics of patients with hip fracture. Acknowledgment This study was supported by OTC grants (ref. 469508 and ref. 2008-KSWH) grants. doi:10.1016/j.bone.2010.09.200
184 Osteoprotegerin deficiency attenuates the dual effect of strontium on bone Songlin Peng1, X. Sherry Liu2, Guangqian Zhou1, Zhaoyang Li1, Keith D.K. Luk1, X. Edward Guo2, W. William Lu1 1 Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China 2 Bone Bioengineering Lab, Department of Biomedical Engineering, Columbia University, New York, NY, USA Objective: Strontium (Sr) exerts an anabolic and anti-resorptive (dual) effect on bone but the mechanism remains unknown. Osteoprotegerin (OPG) expressed by osteoblasts plays an important role in regulating bone homeostasis by inhibiting osteoclastogenesis and bone resorption. This study aims at evaluating the role of OPG in the dual effect of Sr on bone. Methods: Six-week-old OPG knockout (KO) male mice and their wild-type (WT) littermates were orally treated with vehicle (Veh) or Sr compound (4 mmol/kg) daily for 8 weeks. Bone mass and microstructure in lumbar spine (L4) and proximal tibiae were analyzed with micro computed tomography (μCT). Bone remodeling was evaluated with serum biochemical
analysis, static and dynamic bone histomorphometry. Osteoclasts' differentiation potential and gene expression were analyzed in the bone marrow cells. Results: The findings demonstrate that Sr compound treatment results in greater bone volume and trabecular number than Veh treatment in WT mice. The anabolic response of trabecular bone to Sr treatment is attenuated in KO mice. Although Sr treatment significantly decreases in vitro osteoclastogenesis and bone resorption in WT mice, such an effect is attenuated in KO mice. Furthermore, Sr treatment profoundly increases OPG gene expression in the tibiae and OPG protein levels in the serum of WT mice. Conclusion: This study concludes that OPG is involved in the crosstalk between osteoblasts and osteoclasts, which provides a novel mechanism for the dual effect of Sr on bone metabolism. doi:10.1016/j.bone.2010.09.201
185 The study of ultrasound speed and microstructure parameters in cancellous bone during decalcification Haijun Niu, Xiaoning Shao, Yubo Fan, Deyu Li, Fang Pu Beihang University, Beijing, China Objectives: Osteoporosis is a systemic skeletal disease characterized by low bone mass and microstructure deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. In recent years, ultrasound has become a widely suggested noninvasive tool for the assessment of bone status and diagnosis of osteoporosis. However, the accuracy of the ultrasound bone measurement is still a controversial issue. Part of the reason is that the relation between ultrasound and bone microstructure is not so clear. The aim of this in vitro study is to investigate the correlations between quantitative ultrasound (QUS) parameters and microstructure parameters of defatted swine cancellous bone during the process of decalcification. Method: Cancellous bone specimens were obtained from the proximal ends of fresh swine tibia which were defatted by an ultrasonic cleaning machine. All the samples were treated with a 0.1 mol/L buffered solution of Ethylene Diamine Tetraacetic Acid (EDTA) to reduce mineral content which was replaced every 2 h until BMD was less than 0.1 g/cm3. The ultrasound experimental system included one 400 MHz AD card (CompuScope 12400, Gage, Canada), one ultrasound pulse transmitter/receiver (Model 5800, Olympus, USA) and a pair of coaxially aligned focusing transducers (V303-SU, Panametrics, USA) with the center frequencies of 1 MHz. Transmitted signals were recorded with the sampling frequency of 200 MHz and the speed of sound (SOS) was calculated. Microstructure parameters of specimens were obtained by a Micro-CT system (SkyScan 1076, Belgium). Bone mineral density (BMD) and microstructure parameters like Bone Volume/Tissue Volume (BV/TV), Trabecular Number (Tb.N), Bone Surface/Volume ratio (BS/BV), Bone Surface Density (BS/TV) and Degree of Anisotropy (DA) were calculated based on reconstructed pictures. Ultrasonic and Micro-CT measurements were applied before decalcification and at the interval of changing the decalcification solution. Results: With the loss of calcium in the bone samples, SOS showed a downtrend. Meantime, the structure of the trabeculae were destroyed step by step; the values of BMD decreased significantly from 0.2462 to 0.1272. BV/TV and Tb.Th showed a gradual downtrend. In contrast, BS/BV and Tb.Pf generally showed an uptrend. Conclusion: As calcium flowed away, SOS showed a strong correlation with some microstructure parameters such as BMD, BV/TV and Tb.Th. Tb.Th is an important microstructure parameter representing the thickness of the trabecula. The result also shows a linear relation between SOS and Tb.Th. However, the correlation between SOS and Tb.Pf and BS/BV is not significant. The
178 Effect of hepcidin on proliferation, apoptosis, mineralization and gene expression of osteoblast (hFOB1.19) in vitro Yong Ma, YiuJia Xu The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China Objective: In recent years, the relationship between iron metabolism and bone metabolism has had many developments and hepcidin has been known as a small peptide hormone that functions as a homeostatic regulator of iron metabolism. To research relationship between iron metabolism and bone metabolism, hepcidin and osteoblast were selected as research objects. In this research, we investigate effect of hepcidin on proliferation, apoptosis, mineralization and influence on COLI, BGP and OPG gene expression of osteoblast (hFOB1.19) in vitro, providing research data about iron related bone metabolism. Methods: After hFOB1.19 osteoblasts were cultured in vitro, we treated the cells with hepcidin (0 nmol/L, 100 nmol/L and 200 nmol/L) for 24 h and 48 h. MTT assay was used to detect each hole that absorb light OD value in enzymelinked immunosorbent detector at 490 nm which represented cell proliferation viability. When the cells, induced by serum-free hunger, were added with hepcidin for 48 h, we detected the influence of hepcidin on osteoblast apoptosis by using Annexin intervention V/PI staining and flow cytometry. We intervened in osteoblasts with hepcidin for 15 days and observed calcium nodules by von Kossa staining assay. We counted the number of calcium nodules to investigate effect of hepcidin on cell mineralization. At the same time, when the cells were treated with hepcidin for 72 h, we detected gene expression of COLI, BGP and OPG by RT-PCR. Results: The OD value indicating cell proliferation viability had no difference in different groups at 24 h and 48 h. As compared to the control, apoptosis rate of cells added with hepcidin were lower. Osteoblasts apoptosis rate dropped from the control group 7.32% to 100 nmol/L 4.99% and 200 nmol 2.46%. Data acquisition in twodimensional scatterplot chart showed that apoptotic cell numbers were fewer in hepcidin groups and effect on anti-apoptosis in 200 nmol/L was stronger than that of 100 nmol/L. There were significant differences as compared to the control group. The numbers of calcium nodules of cells treated with hepcidin were more than the controls and they had significant differences. The number increase of calcium nodules is the most obvious in 200 nmol/L. Intervention of hepcidin in hFOB1.19 cells culture, as compared with the control group, the relative content of COL1, OPG, BGP mRNA boost. In this experiment, osteogenesis-related gene expression raise positive with hepcidin concentration increase. There were significant differences in hepcidin (100 nmol/L, 200 nmol/L, 400 nmol/L) as compared with the control group. Although there was an increase, there was no significant difference in 50 nmol/L concentration. Conclusion: Hepcidin can decrease rate of apoptosis and enhance the calcium nodules of osteoblast 1.19, although hepcidin had no effect on cell proliferation viability. Hepcidin protected osteoblasts by reduce rate of apoptosis and promoted the formation of mineralization by increasing calcium nodules. In this study, hepcidin, which was an important hormone in iron metabolism can increase COL1, OPG, BGP gene expression of hFOB1.19, might promote osteoblast function, participating in the bone metabolism process. Based on our research of the influences on osteoblasts (hFOB1.19) metabolism, hepcidin regulation might be an important intervention spot on iron metabolism and bone metabolism.
doi:10.1016/j.bone.2010.09.198
S407
179 Clinical features and SQSTM1 gene mutation filter of sporadic and familial cases of Paget's disease of bone Jie-mei Gu, Zhen-lin Zhang The Department of Osteoporosis, Metabolic Bone Disease and Genetic Research Unit, Shanghai JiaoTong University Affiliated Sixth People's Hospital, Shanghai, China Objective: To improve our knowledge of diagnosis and treatment of Paget's disease of bone (PDB), and find possible pathogenic gene, we analyzed clinical features and did SQSTM1 gene mutation filter of 12 sporadic cases and 3 familial cases of PDB. Methods: Twelve sporadic cases and 3 cases of a PDB family were diagnosed and the clinical manifestation, X-ray character, change of the biochemical marker of bone turnover and the treatment of diphosphonates were all employed. And on all the cases we performed a SQSTM1 gene mutation filter. Results: Sporadic cases: 1) 8 males and 4 females, average age 63.7 ± 14.8 years. 2) The average course of disease was 5.0 ± 3.8 years. It was clinically manifested by the pain and deformity of the bone involved. 3) Bone lesions of 5 patients were limited to a single site, while others had multiple bone lesions. The most common sites were pelvis, femurs and tibia; the second most common sites were spine and skull. 4) X-ray imaging showed impaired trabecular bone structure of disordered, enlargement and deformation of the skull; tubular bones had cortical thickening, expansion or enlargement; in the spine, an involved vertebral body is typically enlarged and a picture frame effect may occur due to cortical thickening of the vertebral bodies. 5) Nine of the patients had radionuclide bone scans. The typical appearance was one of markedly increased tracer uptake in the affected bones. 6) Serum alkaline phosphatase (ALP) was detected in all patients before therapy, from 93 u/L to 1366 u/L (median 323 u/L). Nine patients were treated with diphosphonates, and their ALP was significantly decreased. 7) All the patients had SQSTM1 gene mutation filter, only a 53-year-old man had gene mutation. Familial case: We obtained a Chinese pedigree with PDB in 45 members of 3 generations. Three patients were diagnosed, including two men and one woman. The three patients were all in the second generation. The average course of disease was 3.3 ± 2.3 years. The three cases all had concealment onset, gradually difficulty in walking and were weak in the legs. They also felt an ache in their backs. Typical appearance in plain radiography and radionuclide bone scans were found in these cases. ALP was high in case 1 and case 3, and decreased after treatment. The three cases all received diphosphonates to reduce the pain. We didn't find SQSTM1gene mutation in these three cases. Conclusion: PDB is rare in China. The important diagnostic evidence is the remarkable change of biochemical marker of bone turnover and the typical radiological display. Diphosphonates in the vein is effective on Paget's disease of bone. It was the first time to report SQSTM1 gene mutation of sporadic cases of PBD in Chinese Han ethnic people. There may be other gene mutation in familial cases that needs to be further researched.
doi:10.1016/j.bone.2010.09.199
180 Bone microarchitecture in hip fracture patients — An application of non-invasive high-resolution peripheral quantitative computed tomography (HR-pQCT) Vivian Hung, Elaine Tsz-ning Fong, Wing-hoi Cheung, Kwok-sui Leung, Ling Qin The Chinese University of Hong Kong, Hong Kong, China Objective: Hip fracture is the commonest type of osteoporotic fractures. The aim of this study is to use high-resolution peripheral
S408
Abstracts / Bone 47 (2010) S385–S458
quantitative computed tomography (HR-pQCT) to evaluate the bone quality profile of subjects with and without non-traumatic hip fracture non-invasively. Methods: Hip fractured postmenopausal women (n = 25) and age- and gender-matched normal controls (n = 38) were recruited. The bone quality at the non-dominant distal radius and non-fracture (fracture group)/non-dominant (control group) of distal tibia were measured by HR-pQCT (XtremeCT, Scanco Medical AG). HR-pQCT, with 82 mm resolution, provided volumetric trabecular BMD (Dtrab), cortical BMD (Dcort), bone to tissue volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp). Independent t-test was used for between-group analysis. Results: Similar age and body weight were found in both groups. At the distal tibia, all vBMDs, including total BMD, Dtrab and Dcort, were significantly lower in the hip fracture (HF) group (−26.2 to −7.5%; all, p < 0.02). For bone microarchitecture parameters, lower BV/TV (−21.2%; p = 0.02) and higher Tb.Sp (+56.4%; p = 0.02), were found in the HF group. Moreover, the HF group had significantly smaller cortical bone area (−30.5%; p < 0.01) and cortical thickness (−32.5%; p < 0.01), while bone area in the trabecular region was significantly larger (+ 14.5%; p = 0.02) as compared with the control group. Similar findings were also found at the distal radius. Discussion and conclusion: Lower vBMDs and poor bone microarchitecture at both distal tibia and radius were found in the hip fracture group as compared with those of the control. In addition to BMD, our results suggested that poor bone microarchitecture was associated with hip fracture. Of all the parameters, trabecular separation was more sensitive in detecting patient with hip fracture. Smaller cortical bone area and cortical thickness together with larger trabecular bone area are typical structural deterioration in osteoporotic patients with significant trabecularization or osteoporosis of cortical bone. Our HR-pQCT findings may imply cortical thinning was also observed in hip fracture group. Bone structural information and BMD, measured by non-invasive HR-pQCT with low radiation, help us understand the characteristics of patients with hip fracture. Acknowledgment This study was supported by OTC grants (ref. 469508 and ref. 2008-KSWH) grants. doi:10.1016/j.bone.2010.09.200
184 Osteoprotegerin deficiency attenuates the dual effect of strontium on bone Songlin Peng1, X. Sherry Liu2, Guangqian Zhou1, Zhaoyang Li1, Keith D.K. Luk1, X. Edward Guo2, W. William Lu1 1 Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China 2 Bone Bioengineering Lab, Department of Biomedical Engineering, Columbia University, New York, NY, USA Objective: Strontium (Sr) exerts an anabolic and anti-resorptive (dual) effect on bone but the mechanism remains unknown. Osteoprotegerin (OPG) expressed by osteoblasts plays an important role in regulating bone homeostasis by inhibiting osteoclastogenesis and bone resorption. This study aims at evaluating the role of OPG in the dual effect of Sr on bone. Methods: Six-week-old OPG knockout (KO) male mice and their wild-type (WT) littermates were orally treated with vehicle (Veh) or Sr compound (4 mmol/kg) daily for 8 weeks. Bone mass and microstructure in lumbar spine (L4) and proximal tibiae were analyzed with micro computed tomography (μCT). Bone remodeling was evaluated with serum biochemical
analysis, static and dynamic bone histomorphometry. Osteoclasts' differentiation potential and gene expression were analyzed in the bone marrow cells. Results: The findings demonstrate that Sr compound treatment results in greater bone volume and trabecular number than Veh treatment in WT mice. The anabolic response of trabecular bone to Sr treatment is attenuated in KO mice. Although Sr treatment significantly decreases in vitro osteoclastogenesis and bone resorption in WT mice, such an effect is attenuated in KO mice. Furthermore, Sr treatment profoundly increases OPG gene expression in the tibiae and OPG protein levels in the serum of WT mice. Conclusion: This study concludes that OPG is involved in the crosstalk between osteoblasts and osteoclasts, which provides a novel mechanism for the dual effect of Sr on bone metabolism. doi:10.1016/j.bone.2010.09.201
185 The study of ultrasound speed and microstructure parameters in cancellous bone during decalcification Haijun Niu, Xiaoning Shao, Yubo Fan, Deyu Li, Fang Pu Beihang University, Beijing, China Objectives: Osteoporosis is a systemic skeletal disease characterized by low bone mass and microstructure deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. In recent years, ultrasound has become a widely suggested noninvasive tool for the assessment of bone status and diagnosis of osteoporosis. However, the accuracy of the ultrasound bone measurement is still a controversial issue. Part of the reason is that the relation between ultrasound and bone microstructure is not so clear. The aim of this in vitro study is to investigate the correlations between quantitative ultrasound (QUS) parameters and microstructure parameters of defatted swine cancellous bone during the process of decalcification. Method: Cancellous bone specimens were obtained from the proximal ends of fresh swine tibia which were defatted by an ultrasonic cleaning machine. All the samples were treated with a 0.1 mol/L buffered solution of Ethylene Diamine Tetraacetic Acid (EDTA) to reduce mineral content which was replaced every 2 h until BMD was less than 0.1 g/cm3. The ultrasound experimental system included one 400 MHz AD card (CompuScope 12400, Gage, Canada), one ultrasound pulse transmitter/receiver (Model 5800, Olympus, USA) and a pair of coaxially aligned focusing transducers (V303-SU, Panametrics, USA) with the center frequencies of 1 MHz. Transmitted signals were recorded with the sampling frequency of 200 MHz and the speed of sound (SOS) was calculated. Microstructure parameters of specimens were obtained by a Micro-CT system (SkyScan 1076, Belgium). Bone mineral density (BMD) and microstructure parameters like Bone Volume/Tissue Volume (BV/TV), Trabecular Number (Tb.N), Bone Surface/Volume ratio (BS/BV), Bone Surface Density (BS/TV) and Degree of Anisotropy (DA) were calculated based on reconstructed pictures. Ultrasonic and Micro-CT measurements were applied before decalcification and at the interval of changing the decalcification solution. Results: With the loss of calcium in the bone samples, SOS showed a downtrend. Meantime, the structure of the trabeculae were destroyed step by step; the values of BMD decreased significantly from 0.2462 to 0.1272. BV/TV and Tb.Th showed a gradual downtrend. In contrast, BS/BV and Tb.Pf generally showed an uptrend. Conclusion: As calcium flowed away, SOS showed a strong correlation with some microstructure parameters such as BMD, BV/TV and Tb.Th. Tb.Th is an important microstructure parameter representing the thickness of the trabecula. The result also shows a linear relation between SOS and Tb.Th. However, the correlation between SOS and Tb.Pf and BS/BV is not significant. The