The effects of romosozumab combined with active vitamin D3 on fracture healing in ovariectomized rats.

BACKGROUND: In this study, we investigated the potential acceleration of fracture healing and bone mineral density-increasing effects of romosozumab and active vitamin D3 combination therapy for fractures in ovariectomized rats. METHODS: Ovariectomy was performed on 40 24-week-old female Sprague-Dawley rats. After 8 weeks, the rats were subjected to periosteum removal and osteotomy of the femoral shaft followed by osteosynthesis with intramedullary nailing to create fracture models. The rats were then divided into four groups: C group (control), R group (receiving romosozumab at 25 mg/kg once a month via subcutaneous injection), VD group (receiving active vitamin D3 at 0.2 µg/kg twice a week via subcutaneous injection), and R + VD group. Further, 10 rats were included in a sham group. At 10 weeks after the intervention, both femurs were removed and blood samples were collected from all rats. Soft X-ray imaging was used to evaluate bone union, and microcomputed tomography (micro-CT) was used for bone morphometric evaluation. Toluidine blue staining was used for the histopathological evaluation of the undecalcified specimens, and bone turnover marker levels were measured using enzyme-linked immunosorbent assay. RESULTS: Bone morphometry analysis via micro-CT revealed increased mineral density of the trabecular bone in the R + VD group femurs, demonstrating the effectiveness of romosozumab plus active vitamin D3 combination therapy. However, there were no differences in bone union evaluated using soft X-ray imaging, indicating no acceleration of fracture healing. CONCLUSIONS: Although romosozumab and active vitamin D3 combination therapy increased trabecular bone volume, there was no evidence on its ability to accelerate fracture healing.

Zwitterionic Poly(carboxybetaine) Brush/Albumin Conjugate Films: Structure and Lubricity.

Artificial cartilages build up a highly lubricious system with the harmony of biomacromolecules and water. Bioconjugate thin films composed of a zwitterionic poly(carboxybetaine methacrylate) (PCB) brush platform and bovine serum albumin (BSA) were designed. BSA conjugation to the PCB brush chains was achieved by carbodiimide chemistry to give PCB brush/BSA conjugate films. The PCB brush/BSA conjugate films exhibited adaptable interfacial properties due to the amphiphilic nature of BSA. Neutron reflectivity showed that BSAs were localized at the liquid side of the conjugate films in PBS and the BSA conjugation slightly reduced the water content of the top layer, while the swollen state of the carpet PCB brush layer remained unchanged. The PCB brush/BSA conjugate films showed improved lubricity in the boundary lubrication mode but slightly worse fluid lubrication induction properties. This conjugate film could be a model system for the investigation of zwitterion/protein composite interfaces and is worth developing biomaterials that require lubrication in vivo.