Figure 1: (A) Representative DAF registrations. The time dependence of the changes in DAF-FM fluorescence’s was determined in HaCaT cells. The 5 minutes treatment with Pb led to a significantly increased DAF signal (*p<0.05). Finally, there was a time-dependent increase in NO release under treatment with Pb (n=25 cells per examination) in comparison to control (H2O, n=25 cells per examination). Repeated measures ANOVA with covariance type AR were applied to evaluate group (H2O, Pb) differences in the mean values of DAF-FM fluorescence (intensity). The main effects of treatments were significant at level 5%. The significant result (*p<0.05) was marked with asterisk. (B) Photomicrographs of the DAF-stained HaCaT cells under treatment with Pb at time point 0 and 360 seconds and of H2O treated controls (C) also at time point 0 and 360 seconds (Magnification=400 fold; Bars=100 μm).