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The objective of this study was to investigate the relationship between serum levels of OPG, TGF- β 1, and TGF- β 2 and BMD decrease rate (BDR) in native Chinese women. This cross-sectional study was performed on 465 healthy native Chinese women aged 35-80 years. Serum levels of OPG, TGF- β 1, and TGF- β 2 were determined. BDR was measured by DXA at the posteroanterior spine, hip, and distal forearm. At all skeletal sites tested, there was a negative correlation between BDR and serum levels of both OPG (r = -0.122 to -0.230, all P = 0.007-0.000) and TGF- β 2 (r = -0.100 to -0.173, all P = 0.029-0.000) and a positive correlation between BDR and serum TGF- β 1 (r = 0.245 - 0.365, all P = 0.000). After adjustment for age and BMI, there were no statistically significant correlations between serum levels of OPG or TGF- β 2 and BDR. However, statistically significant correlations between serum TGF- β 1 and BDR at the lumbar spine and ultradistal forearm remained. Multiple linear regression stepwise analysis showed that serum OPG could explain 1.4-3.7% of BDR variation. Serum TGF- β 1 was a positive determinant of BDR and could explain 5.3-13.3% of BDR variation.

Objective: To explore the molecular mechanism of glucocorticoid (GC)-induced osteoporosis (GIOP)., Methods: Thirty-two female SD rats after matching body weight were divided randomly into three groups: baseline group (n = 10), control group (n = 11) and GC-treated group (n = 11). The administration time was 9 weeks. Bone mineral density (BMD) was measured with dual energy X-ray absorptiometry. A high resolution micro-CT was used to quantify the densitometric and microarchitectural properties of trabeculae in the proximal metaphysis of right tibia. In situ hybridization histochemistry and immunohistochemistry were used to detect the expression of cannabinoid type 1 receptor (CB1R) in the proximal metaphysis of left tibia., Results: At the end of the experiment, whole-body BMD in vivo in the control group [(0.156 +/- 0.008) g/cm(2)] was higher than that in the baseline group [(0.147 +/- 0.006) g/cm(2)], while the whole-body BMD in vivo [(0.147 +/- 0.006) g/cm(2)] and total BMD in vitro at femurs in the GC-treated group [(0.220 +/- 0.011) g/cm(2)] was lower than those in the control group [(0.240 +/- 0.024) g/cm(2)]. Compared with the baseline group and control group, there was a remarkable decrease in the volumetric BMD, tissue BMD, trabecular number and trabecular connectivity (P < 0.05) in the GC-treated group, while there was a significant increase in trabecular separation (P < 0.05) and trabecular thickness also increased in the proximal metaphysis of tibiae in the GC-treated group. The expression level of CB1R mRNA and protein in osteoclasts in the GC-treated group was markedly higher than that in the baseline group and control group (P < 0.05). There was a close correlation between the expression level of CB1R mRNA, protein in osteoclasts and some microarchitectural parameters in the proximal metaphysis in the GC-treated group (P < 0.05)., Conclusions: The administration of GC is associated with a decrease in BMD and deterioration in microarchitecture of trabecular bone in rats tibiae. Glucocorticoid may up-regulate the CB1R expression level in osteoclasts and this may be a kind of molecular mechanism of GIOP.

Objective: To investigate the Dynamic effects of glucocorticoid (GC) on bone mineral density and microarchitecture time-related changes of trabecular bone in bone mineral density (BMD) and microarchitecture in glucocorticoid-treated rats., Methods: Fifty-two 3.5-month-old female SD rats were randomly divided into 3 groups. Ten rats were killed at the beginning of experiment with their right tibiae taken out as the baseline group; 22 rats underwent subcutaneous injection of methylprednisolone once daily (GC-treated group), and the other 20 rats underwent subcutaneous injection of normal saline once daily as control group. One and 9 weeks after the beginning of experiment 11 and 10 rats from GCT Group and control group each were killed with their right tibiae taken out. High resolution micro-CT was used to identify the densitometric and microarchitectural properties of the trabecula in the proximal metaphysic of tibia., Results: Compared with the control group the values of volumetric BMD (vBMD), tissue BMD (tBMD), bone volume fraction (BVF), trabecular number (Tb.N), degree of anisotropy (DA), and trabecular connectivity (Conn.D) in the trabecular bone at different time-points, of the GCT group all decreased; and the values in the ninth week were the lowest (all P < 0.05). The values of trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and structure model index (SMI) at different time-points of the GCT group were higher than those of the control group. A time-related analysis within the GCT group showed there was a declination in BVF, Conn.D, Tb.N, and DA with administration time, but Tb.Th and Tb.Sp were increased significantly (all P < 0.05). The mean values of Tb.Th in the first week and the ninth week of GCT Group were (0.076 +/- 0.020) mm and (0.086 +/- 0.026) mm respectively, both higher than the baseline value [(0.067 +/- 0.014) mm] and the values of the control group in the first and ninth weeks [(0.075 +/- 0.022) mm and (0.072 +/- 0.009) mm respectively]., Conclusion: Administration of GC time dependently decreases the BMD and causes deterioration in microarchitecture of trabecular bone; and the remaining trabeculae seem thicken to increase their strength as compensation.

Objective: To study the nanomechanical properties of the vertebral trabeculae of ovariectomized rat using nanoindentation., Methods: Twenty 10-month-old SD rats were randomly divided into 2 equal groups: ovariectomized (OVX) group and Sham operation (SHAM) group. Fifteen weeks post-operationally dual energy X-ray absorptiometry was used to measure the bone mineral density (BMD) of the total body and of the sixth lumbar vertebra. Then the rats were killed. The BMD values of the sixth lumbar vertebrae were measured by DXA. Bone histomorphometry was performed on the proximal metaphysis of the right tibia. Three of the sixth lumbar vertebrae were randomly selected from each group and embedded in methyl methacrylate. Each vertebra was cut into two parts along the transverse direction in the middle point of longitudinal axis so as to expose the trabeculae on the cross section. The lower part was polished, trabeculae were randomly selected from 4 places, and 5 points from each place were randomly selected to undergo nanoindentation so as to measure the nanomechanical properties., Results: Compared with the SHAM rats, the BMD of the sixth lumbar vertebra of the OVX rats was reduced significantly (P < 0.05). The histomorphometry of the tibia showed an increase in trabecular separation and a decrease in trabecular bone area fraction (both P < 0.05); the trabecular number and thickness decreased in these 2 groups, however, without significant difference between them. Nanoindentation tests showed that the values of hardness and elastic modulus of the trabeculae of the OVX rats were 0.91 GPa +/- 0.13 GPa and 21.01 GPa +/- 2.48 GPa respectively, not significantly different from those of the SHAM rats, 0.90 GPa +/- 0.09 GPa and 22.03 GPa +/- 2.44 GPa respectively., Conclusion: A novel technique, nanoindentation is able to directly measure the nanomechanical properties of trabeculae. Estrogen deficiency after ovariectomy induces significant osteoporotic change, but has no significant influence on the trabecular nanomechanical properties.

Objective: To characterize the clinical manifestations, features of roentgenography and MR imaging, and the pathology of articular cartilage and matrix of spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA), to screen the mutations of the disease-causing CCN6 gene, and try to elucidate the molecular pathogenesis of SEDT-PA., Methods: A questionnaire survey on the clinical manifestations and history was conducted among a pedigree of SEDT-PA with 57 persons (53 living members) in tolal, including 2 probands, a 19-year old female and a 9-year old male. Physical examination and roentgenography and MR imaging were used on the 2 probands to characterize the features of their joints and articular cartilage. The femoral head extracted during replacement of hip of the proband 1 underwent hematoxylin-eosin staining and toludine blue (TB) staining to observe the pathological changes and ultra-microstructure of the articular chondrocytes and cartilage matrix using electron microscopy. Peripheral blood samples were collected from these 53 living members and 100 healthy controls. PCR was used to examine and sequence the exons of CCN6. 3D-conformational illustration of mutant CCN6 proteins were predicted using the Prospect Software., Results: The clinical manifestations, radiology, and MR imaging established the diagnosis of SEDT-PA. Pathologic examination demonstrated that the articular cartilage chondrocytes became hyper-proliferative and immature, while the density and diameter of matrix collagens were dramatically decreased. Mutation studies showed the two probands carried a deletion (840delT) mutation in maternal allele, that caused the truncated CCN6 protein to miss 43 residues in C-terminus; and a substitution mutation (1000T-->C, Ser334Pro) in paternal allele, which was also inherited down to other 4 members in the SEDT-PA kindred. The predicted 3D-conformational changes of the truncated mutant and the Ser334Pro mutant CCN6 proteins demonstrated that in comparison with the wild CCN6 protein, the single long peptide loop in the region from signal peptide to the beginning 24 amino acid residues in the first domain (IGFBP) was subjected to folding into two smaller cross-loops accompanied with a much shorter C-terminus in 840 delT truncated mutant CCN6 protein, and no substantial 3D-conformational change of Ser334Pro mutant CCN6 protein was detected except for the C-terminal peptide towards the opposite direction., Conclusion: Novel 840delT mutation of CCN6 gene is the leading cause of SEDT-PA though coexistence of T1000C substitution is necessary for the clinical onset of SEDT-PA, in which marked abnormalities of cartilage chondrocytes and matrix are morphologically and functionally presented.

Objective: To investigate the pathway and mechanism of parathyroid hormone (PTH) in regulating bone resorption., Methods: We observed the regulative effects of PTH on the expression of osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) and their related cytokines (M-CSF and TRAIL) in human osteoblasts (HOBs). The expressions of OPG, OPGL, M-CSF, and TRAIL mRNA were determined by RT-PCR. The expressions of OPG and OPGL proteins were measured by Western blotting., Results: PTH down-regulated the expression of OPG but up-regulated the expressions of OPGL, M-CSF and TRAIL in HOBs., Conclusion: PTH can promote the bone resorption by decreasing the expression of OPG, increasing the expressions of some bone-resorbing cytokines such as OPGL, M-CSF, and TRAIL in osteoblasts, and then stimulating the osteoclast differentiation and activity.

Objective: To determine the effects of long-term estrogen deficiency and replacement therapy of compound nylestriol tablet or low-dose 17 beta-estradiol on the expression of nerve growth factor (NGF) in rat hippocampal formation., Methods: Fifty 7 month-old female Sprague-Dawley rats were randomly divided into 5 groups: normal control, sham operated (SHAM), ovariectomized (OVX), OVX plus 17 beta-estradiol (OVX/ERT), and OVX plus compound nylestriol tablet (OVX/NL) groups. Immunohistochemistry of NGF was used to quantitatively determine the levels of expression of NGF using cell counting and imaging system in ovariectomized rat hippocampal formation., Results: The number and optical density of NGF-positive neurons of all hippocampal subregions and dentate gyrus in OVX rats were obviously lower than those of the normal control, SHAM, OVX/NL, and OVX/ERT rats., Conclusion: Long-term estrogen deficiency can lead to a decrease of NGF expression in hippocampal formation, while the replacement of low-dose 17 beta-estradiol or compound nylestriol tablet can equally preserve the expression of NGF to a normal level, showing a neurotrophic effect of estrogen.

Objective: To establish a new technique for evaluation of the tensile property of articular cartilage using digital speckle correlation method (DSCM)., Methods: Three specimens of whole layer articular cartilage of the size of 10 mm x 4 mm were prepared from the cartilage of head of femur replaced from a 52-year-old male suffering from fracture of neck of femur (old control), the amputated tibia plateau of a 16-year-old female suffering from osteosarcoma (young control), and the cartilage of head of femur of a 19-year-old female suffering from spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA) and then underwent DSCM in U and V fields., Results: The specimens of the 2 controls showed a smooth surface of cartilage and homologous deformation while the specimen of the SEDT-PA patient showed a rough surface of cartilage and deformation with increased undulation. Under a changed loading of 3.3 N the values of average strain of cartilage were 3800, 8800, and 9500 micro epsilon, and the values of tensile elastic modularity were 227.23, 89.59, and 127.25 MPa respectively for the old control, young control, and SEDT-PA patient. The numbers of pixel in U field after 20 pixels were moved in the X direction were significantly different between the old control subject and the SEDT-PA patient (0.101 +/- 0.022 vs 0.220 +/- 0.053, P = 0.023). The numbers of pixel in V field after 20 pixels were moved in the Y direction were significantly different among the old control subject and the SEDT-PA patient. Differences were also significant among the three kinds of cartilage (0.055 +/- 0.018, 0.196 +/- 0.057 vs 0.658 +/- 0.144, both P < 0.05)., Conclusion: DSCM is a reliable technique to measure the tensile property of articular cartilage, especially for evaluation of small specimens. SEDT-PA is characterized by a dramatic decrease of tensile property, causing destruction and loss of the articular cartilage.

Objective: To investigate the effects of compound nylestriol tablet (CNT), containing nylestriol and levonorgestrel with a ratio of 1:0.3) and its components on the osteoporotic rat model induced by retinoic acid (RA) and ovariectomy (OVX)., Methods: We randomly divided 144 female SD rats (aged 7-month-old) into 12 groups (12 in each). In addition, 120 female SD rats aged 4-month were randomly divided into 10 groups (10 in each). Three dosage levels of CNT (0.039, 0.117 and 0.39 mg/kg body weight, daily), nylestriol (NYL, 0.30, 0.09 and 0.03 mg/kg body weight, daily) and levonorgestrel (LEV, 0.09, 0.027 and 0.009 mg/kg body weight, daily) were designed to prevent the bone loss of the osteoporotic rat model induced by RA and OVX respectively. Serum total calcium (Ca), phosphate (Pi), ALP, triglyceride (TG), total cholesterol (TC), HDL-C, total body BMD, isolated left femoral BMD and femoral Ca, and Pi after ashing were determined., Results: Osteoporotic models could be induced by RA (70 mg/kg body weightdaily given intragastrically for 14 days) or by ovariectomy; CNT and its components had the preventive effects on bone loss in both models; The preventive effect of CNT was dose-dependent and stronger than its components; Many observed markers showed us the levels of high and moderate CNT given to be the strongest, corresponding to an optimal choice of the moderate dose CNT about one tablet per week in adult women., Conclusions: CNT therapy can prevent the bone loss of RA-induced and OVX-induced osteoporotic rats, and its therapeutic and preventive effect is better than its components used alone.

Objective: To compare microcrack with bone mineral desity (BMD), bone histomorphometry and biomechanics parameters, and to investigate the potential of microcrack in the evaluation of bone biomechanical quality., Methods: Eight 10-month-old Sprague-Dawley rats were served as baseline controls, and 90 10-month-old rats were randomly divided into A, B, and C groups. Each group comprised ovariectomized (OVX), 17 beta-estradiol treated [EST, 10 micro/(kg x d)] and sham-operated (SHAM) subgroups. Rats from groups A,B and C were killed at the 3rd, 15th and 21st week post-operatively. Total body and lumbar vertebral BMD were measured before being killed, and BMD of isolated lumbar vertebrae and tibiae were measured after killing. Bone histomorphometry of the proximal end of isolated right tibia was performed,and compression test was carried out on the isolated 5th lumbar vertebra (L5). After fatigue damage, the isolated 4th lumbar vertebra was stained by en bloc basic fuchsin staining, and microcrack density (Cr. Dn) and microcrack surface density (Cr. SDn) were de- termined on the bone tissue sections. Bone parameters in each subgroup of rats were observed at different time., Results: (1) At the 15th and 21st week post-operatively, multi-part BMD, Cr. Dn and Cr. SDn were higher than those at the 3rd week. (2) At the 15th week, trabecular separation (Tb. Sp) increased, trabecular number (Tb. N) decreased, and the maximum loading level and elastic modulus of vertebra reached the peak. (3) At the 3rd week, Tb. Sp, Cr. Dn and Cr. SDn in the OVX subgroup were greater than those in the EST subgroup, while the percentage of trabecular area (TbTr) in the OVX subgroup was lower than that of the EST and SHAM subgroups. No changes of BMDs and biomechanic parameters were observed among the three subgroups. (4) At the 15th week, multi-part BMD and maximum loading level in the OVX and EST subgroups were lower than those in the SHAM subgroup, while elastic modulus, bone histomorphometry parameters, Cr. Dn and Cr. SDn had no change among the three subgroups. (5) At the 21st week, multi-part BMDs, Tb. N and TbTr in the OVX subgroup were smaller than those in the EST and SHAM subgroups. Tb. Sp, bone formation rate, mineral apposition rate, percent labeled perimeter,Cr. Dn and Cr. SDn in the OVX subgroups were greater than those in the EST and SHAM subgroups. Maximum loading level and elastic modulus of vertebra in EST and OVX subgroups were lower than those in the SHAM subgroup. There were no significant differences in all of these parameters Microcrack can be regarded as an alterative between the EST and the SHAM subgroup. Conclusion parameter in the evaluation of bone biomechanical quality.