Fig. 1

Mechanical stretching stress induced intervertebral disc inflammation and degeneration in rat nucleus pulposus cells. The cells in different groups were stretched mechanically by 1000µ, 2000µ, 4000µ and 6000µ respectively for 12 h and 24 h. CCK-8 was used to measure the cell viability (a), ELISA was used to measure the level of TNF-α (b), Real-time PCR was used to measure the mRNA expressions of Aggrecan (c) and MMP-3. Data are presented as mean ± SD. *p < 0.05, **p < 0.01, ***p < 0.001 compared to control