The response of nucleus pulposus cell senescence to static and dynamic compressions in a disc organ culture.

BACKGROUND: Mechanical stimuli obviously affect disc nucleus pulposus (NP) biology. Previous studies have indicate that static compression exhibits detrimental effects on disc biology compared with dynamic compression.

OBJECTIVE: To study disc NP cell senescence under static compression and dynamic compression in a disc organ culture.

METHODS: Porcine discs were cultured and subjected to compression (static compression: 0.4 MPa for 4 hours once per day; dynamic compression: 0.4 MPa at a frequency of 1.0 Hz for 4 hours once per day) for 7 days using a self-developed mechanically active bioreactor. The non-compressed discs were used as controls.

RESULTS: Compared with the dynamic compression, static compression significantly promoted disc NP cell senescence, reflected by the increased senescence associated β-galactosidase (SA-β-Gal) activity, senescence-associated heterochromatic foci (SAHF) formation and senescence markers expression, and the decreased telomerase activity and NP matrix biosynthesis.

CONCLUSION: Static compression accelerates disc NP cell senescence compared with the dynamic compression in a disc organ culture. This study provides that acceleration of NP cell senescence may be involved in previously reported static compression-mediated disc NP degenerative changes.

©2018 The Author(s).

KEYWORDS: compression; degeneration; nucleus pulposus; organ culture; senescence

PMID: 29437905 DOI: 10.1042/BSR20180064