| Objective Reports concerning the relationship between osteoporosis (OP) and intervertebral disc degeneration (IVDD) are inconsistent. Accordingly, we assessed whether IVDD is affected by vertebral OP in ovariectomized (OVX) mice and investigated the underlying pathogenesis of IVDD related to OP. Methods Thirty healthy female C57BL/6J mice aged 8 weeks were randomly divided into two groups. Sham operation (CT group, n=15) or bilateral ovariectomy (OVX group, n=15) were implemented individually, and body weight was recorded. At 12 weeks post-surgery, the bone quality and microstructure of the lumbar vertebra as well as endplate, and the volume of L4/5 disc space were evaluated by micro-computed tomography (micro-CT). The occurrence of IVDD and characteristic alterations of the degenerative disc were identified via histiopathological staining. Type II Collagen (Col2) and vascular endothelial growth factor (VEGF) expression in the intervertebral disc were detected by immunehistochemical analyses. Results Compared with CT mice, OVX mice had significantly greater fat tissue accumulated in the abdominal cavity, ovarian atrophy, increased body weight and decreased uterus weight (*P<0.05). The micro-CT analysis showed that the OVX group had vertebral OP, significantly lower BV/TV, Tb.N and CONN.D, and significantly higher Tb.pf and SMI (*P<0.05). The endplate showed obvious microstructure remodeling, with increased porosity and decreased disc volume detected in the OVX group when compared with the CT group (*P<0.05). Likewise, histological evaluation revealed that IVDD occurred at 12 weeks after ovariectomy, with significant degenerative changes of L4/5 disc, ossified and thickened endplate, and degradation and structural disorder of extramedullary matrix of nucleus pulposus. Immunohistochemical analysis demonstrated that Col2 was decreased in the disc of OVX mice while VEGF expression in the endplate was significantly elevated. Conclusion Vertebral OP and osteochondral remodeling of cartilaginous endplate caused an increased permeability at endplate’s bone-cartilage surface which had detrimental effects on the intervertebral disc. |