Abstract:

BACKGROUND: Human intervertebral disc can bear load but lack vessels. The mechanism of intervertebral disc degeneration remains unclear.
OBJECTIVE: To explore the mechanism of disc degeneration through comparison of different biological properties between normal and degenerative nucleus pulposus cells of intervertebral disc.
METHODS: Human normal and degenerative intervertebral disc nucleus pulposus cells were isolated and cultured. Light microscopy, electron microscopy and other morphological methods were used to observe the general morphology and ultrastructure of the cells; growth curve and XTT experiment were used to compare the differences in growth kinetics; the vitality and cell-type Ⅱ collagen and glycosaminoglycan (GAG) mRNA expression was determined.
RESULTS AND CONCLUSION: The degenerative nucleus cells displayed aging appearance at least 2 generations earlier than the normal nucleus cells. Degenerative nucleus pulposus cells showed G1 phase arrest, and the cell could not enter S phase; cell mitosis was inhibited. The growth of degenerative nucleus pulposus cells was faster than normal cells but also aged rapidly. Since the first generation, the degenerative nucleus pulposus cells expressed lower Ⅱ collagen and GAG mRNA than the normal nucleus pulposus cells at the same period. Results show that under in vitro culture conditions, the degenerative nucleus pulposus cells had low proliferative capacity and appeared aging and apoptosis. The best time to reverse the disc degeneration for the intervention trial is before the two-generation.