Background
Mechanical load contributes a lot to the initiation and progression of disc degeneration. Annulus fibrosus (AF) cell biology under mechanical tension remains largely unclear.
Conclusion
High mechanical tension promotes AF cell senescence though suppressing cellular autophagy. The present study will help us to better understand AF cell biology under mechanical tension and mechanical load-related disc degeneration.
Methods
Rat AF cells were cultured and experienced different magnitudes (5% elongation and 20% elongation) of mechanical tension for 12 days. Control AF cells were kept static. Cell proliferation, telomerase activity, cell cycle fraction, and expression of senescence-related molecules (p16 and p53) and matrix macromolecules (aggrecan and collagen I) were analyzed to evaluate cell senescence. In addition, expression of Beclin-1 and LC3, and the ratio of LC3-II to LC3-I were analyzed to investigate cell autophagy.
Objective
The present study was aimed to investigate AF cell senescence under mechanical tension and the potential role of autophagy.
Results
Compared with the control group and 5% tension group, 20% tension group significantly decreased cell proliferation potency and telomerase activity, increased G1/G0 phase fraction, and up-regulated gene/protein expression of p16 and p53, whereas down-regulated gene/protein expression of aggrecan and collagen I. In addition, autophagy-related parameters such as gene/protein expression of Beclin-1 and LC3, and the ratio of LC3-II to LC3-I, were obviously suppressed in the 20% tension group.