Fig. 6.

Apoptosis in foetal neural tissue detected by TUNEL. (A-D) Representative images of TUNEL-stained neural tissue from a NTD case (C and D) and a control (A and B). TUNEL-positive nuclei were in green fluorescent colour and DAPI staining was performed to visualize the total cell number (blue). (E and F) Apoptosis rate was calculated as percent of TUNEL-positive cells out of total cells (median ± range). (E) Correlation between apoptosis level in foetal neural tissue and h_PAHs concentration in maternal serum (n = 39). (F) Comparison of apoptosis rate in foetal neural tissue between NTD-affected foetuses (n =39) and controls (n = 18). Data were presented as box plots, where the boxed represent the 25h to 75th percentiles, the lines within the boxes represent the median, and the lines outside the boxes represent the 10th and 90th percentiles. ^**P < 0.01, ^***P < 0.001, compared with control group.