Abstract
Background
Intervertebral disc cells exist in a challenging physiological environment. Disc degeneration occurs early in life implying that disc cells may no longer be able to maintain a functional tissue. We hypothesise that disc cells have a stress response different from most other cells because of the disc environment. We have compared the stress response of freshly isolated and cultured bovine nucleus pulposus (NP) cells with bovine dermal fibroblasts, representative of cells from a vascularised tissue.
Methods
Freshly isolated and passaged bovine NP cells and dermal fibroblasts were cultured for 3 days then subjected to either thermal stress at 45°C for 1h followed by recovery times of 6, 24 and 48h or nutrient stress involving culture without serum for 6, 24 and 48 h. At each time point, cell number and viability were assessed and heat shock protein 70 (Hsp70) measured in cell lysates by an enzyme-linked immunosorbent assay.
Results
In response to thermal stress, both freshly isolated and passaged dermal fibroblasts and also passaged NP cells showed a rapid elevation of Hsp70. In contrast, freshly isolated NP cells exhibited an attenuated Hsp70 response. With nutrient stress, Hsp70 increased with time in all dermal fibroblasts and passaged NP cells after 24 h, but freshly isolated NP cells responded differently again, producing less Hsp70 than controls.
Conclusion
Freshly isolated bovine NP cells have a reduced response to applied stresses. This pilot study suggests that NP disc cells may have adapted to their physiologically challenging in vivo environment by attenuating their response to environmental stress.
No conflicts of interest
Sources of Funding: The Wolfson Charitable Trust and Genodisc (EC's 7th
Framework Programme (FP7, 2007–2013) under grant agreement no. HEALTH-F2-2008-201626).
This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting.
