Figure 2. This figure reports the effect of NGF on HCEC survival. A: The result of a time-course analysis of HCECs exposed for 4 days to culture medium alone or with 1 ng, 10 ng, or 100 ng of NGF/ml, revealed that at 1 and 10 ng, NGF enhances cell survival, while 100 ng/ml of NGF down-regulates cell survival, compared to control, (*p<0.05). B-D illustrate the structural aspect of these cells exposed to medium alone (B), 10 ng/ml (C), and 100 ng/ml of NGF (D). Note the decreased in cell number in D. Panels E and F illustrate the effect of endogenous NGF inhibition by ANA on HCEC survival. The supplementation of ANA in the culture medium at concentration of 100 ng/ml of medium, significantly (*p<0.05), reduces the number of cells after 4 days in vitro (F), compared to control (E). This effect was statistically significant (G). Scale bars: B-F=25μm.