Serum deprivation of intervertebral disc cells in monolayer cultures was associated with the adoption of a stellate morphology and increased cell senescence. (a) Representative images of control (left panel) and serum-deprived (right panel) cells at day 7; stellate cells are indicated with arrows (original magnification ×200). (b) Representative images of control (left panel) and serum-deprived (right panel) cultures stained for senescence-associated beta-galactosidase (SA-β-gal) activity at day 7 (original magnification ×100). (c) The proportion of SA-β-gal-positive cells was significantly increased in serum-deprived cultures compared with control cultures but was unaffected by glucose or oxygen deprivation. Data are presented as mean ± standard error of the mean. *P < 0.05.