The Role of Continuous Cerebrospinal Fluid Pulsation Stress in the Remodeling of Artificial Vertebral Laminae: A Comparison Experiment

The physiological reconstruction of artificial vertebral laminae without epidural scar tissue formation or spinal cord compression has been challenging. Mechanical stimulations have been reported to play an important role in bone formation and bone remodeling. In this study, we designed a comparison study to investigate the effect of continuous cerebrospinal fluid pulsation (CSFP) stress on the remodeling of artificial vertebral laminae. Mesenchymal stem cells derived from rabbit umbilical cord Wharton's Jelly were induced for osteogenic differentiation for 3 weeks before seeding on the hydroxyapatite-collagen I scaffolds to construct the tissue-engineered laminae (TEL). TEL were then implanted into the fifth rabbit lumbar vertebrae in both CSFP group ( n = 36) and non-CSFP group ( n = 36). De novo laminae were examined through histological and radiographic analysis in the 2nd, 4th, 8th, 12th, 16th, and 24th weeks postimplantation. Our results showed that the osteogenic gene expression levels and cancellous microstructure parameters of newborn laminae in the CSFP group reached the peak and the complete newborn laminae formed in the 12th week. Then the osteoclastic gene expression and osteoclast number of newborn laminae in the CSFP group increased greatly in the 12th week, and were significantly higher compared with the non-CSFP group. After 16 weeks of implantation, the arrangement of trabeculae became organized, and the dura surface of newborn laminae in the CSFP group showed similar curvature and smoothness as the native laminae. In conclusion, continuous CSFP stress played an important role in the physiological reconstruction of artificial vertebral laminae by promoting the remodeling abilities of TEL.