Long-term effects of ovariectomy on the properties of bone in goats

Abstract

Abstract. Large animal models of osteoporosis are essential for osteoporosis research. However, the time required to establish an accurate osteoporosis model is unknown. Therefore, the aim of the present study was to establish a large animal model of osteoporosis in goats. In total, 14 Chinese goats were divided into an ovariectomized (OVX, n=7) or sham-operated (SHAM, n=7) group. Vertebral bodies were used to measure the bone mineral density (BMD) prior to the ovariectomy and at 24 months after the ovariectomy. In addition, the BMD of the femoral neck, femoral diaphysis and tibial diaphysis were measured 24 months postoperatively. Bone samples from the vertebral body, femoral head and femoral neck were scanned by micro-computed tomography (CT) to visualize the trabecular and cortical microstructure. Furthermore, the vertebral body, femoral head, femoral neck and tibial diaphysis were analyzed for mechanical strength. The BMD of vertebral body of the OVX group decreased significantly (P<0.01) at 24 months after the ovariectomy when compared with the baseline measurements. Micro-CT scans of the vertebral body revealed that the bone volume fraction, trabecular number, trabecular thickness and the degree of anisotropy decreased by 37.1, 36.7, 10.5 and 16.5%, respectively (P<0.01) in the OVX group when compared with the SHAM group. Additionally, the specific bone surface and trabecular spacing significantly increased by 37.7 and 62%, respectively in the OVX group (P<0.001). Cortical bone porosity in the vertebral body and femoral neck was greater in the OVX group when compared with the SHAM group (P<0.05). In addition, mechanical testing revealed a statistically significant difference between the vertebral bodies of the OVX group and the SHAM group. In conclusion, the present study demonstrated that an ovariectomy was able to induce significant osteoporosis and deterioration of mechanical properties in the bones of goats.

Osteoporotic Goat Spine Implantation Study Using a Synthetic, Resorbable Ca/P/S-Based Bone Substitute

“…As demonstrated in Figure 9, compared to the control goat, the OVX goat shows significant reductions in Tb.Th, Tb.N, and B.Ar/T.Ar accompanied with an increase in Tb.Sp. Similar changes were observed by Yu et al (2015), wherein a 11.3% decrease in Tb.Th, 36.7% decrease in Tb.N and 37.1% decrease in B.Ar/T.Ar accompanied with a 62% increase in Tb.Sp in the trabeculae of lumbar vertebral body of 7 OVX goats were observed at 24 months post-ovariectomy. No significant differences in Tb.N, Tb.Sp or B.Ar/T.Ar between the OVX_IP goat and the control goat indicate that the architecture of trabecular bone of the CBS-400-implanted OVX_IP goat has substantially recovered to normal levels.…”

“…Apparently, use of larger species, whose bone goes through a coordinated process of bone resorption and new bone formation like humans, would be a better choice for the animal study of osteoporosis. Due to the similarity in biochemical and histopathologic features between osteoporotic goats and humans ( Leung et al, 2001 ), the OVX-induced osteoporotic goat model has been established to assess the healing potential of different bone grafting materials ( Leung et al, 2001 , 2006 ; Li et al, 2010b ; Cao et al, 2012 ; Yu et al, 2015 ).…”

“…The connectivity of trabeculae in the OVX goat is significantly lower than the control goat. This impairment is commonly observed in estrogen deficiency-induced osteoporosis ( Yu et al, 2015 ). The new bone connectivity of the present OVX_IP goat is significantly higher than that of the OVX goat, indicating an improvement in bone connectivity with CBS-400 implant.…”