Figure 3

Time-course effect of growth factors on proliferation of human NP cells (10%FBS/F12) (n = 20). The proliferative response was evaluated by MTT assay at 1-, 3-.5- and 7-day. Results were expressed as the mean optical density of MTT absorbance in growth factors in single or combinations and control wells. * P < 0.05, ** P < 0.01, *** P < 0.001 versus control.