Establishment Of A Vitro Culture System With Rabbit Intervertebral Disc Organ To Analyse Characterization Of Nucleus Pulposus Tissue And Cell

Objective: To establish an organ culture system for intact rabbitintervertebral disc with bony endplate, in which the biologic characters ofnucleus pulposus cells to be observed and the disc degeneration to bemodeled.Method: Rabbit lumbar discs were harvested with bony endplate,cultured under normal osmotic pressure for up to2weeks. Swelling capacityof tissue were recorded for72hours, and disc structure, cell viability,nucleus pulposus cell apoptosis, mRNA of AGG and Coll2were analysedvia histology, CCK-8, transmission electron microscope, TdT-mediateddUTP Nick-End Labeling (TUNEL) kit and RT-PCR at0（fresh）/7d/14d.Results: Organ swelling was stabilized within72hours and weightincreased up18.0%. their weights increased occurred rapidly during the first4hours of culture, and then gradually over the next68hours. discs structureswere maintained over14d, yet NP cell and extracellular matrix were reduced during culture. Cell viability were maintained for54%±9%at7d, however,failed to retain cell viability having only22%±5%after14d(P＜0.05). TheNP cell apoptosis found by Transmission electron microscope, and apoptosiswere increased with the time, the rate of NP cell apoptosis was44.97%±16.45%on the14d vs.5.71%±6.52%on the0d day (P＜0.05). Asignificant downregulated mRNA expression of collagen Ⅱand aggrecan onthe7d and14d was noted(P＜0.05).Conclusion: This organ culture system for intact rabbit intervertebraldisc with bony endplate can be used to model disc degeneration for furtherstudying repair, as morphology, cell viability and responsiveness tobio-active substances were maintained.