Fig. 4.

Quantification of NADH by confocal microscopy. (A) Representative confocal microscopy images of intracellular NADH autofluorescence for unexposed and 2 h UVA-exposed, untreated and pretreated with 10 μM punicalagin. The four images show maps of intracellular NADH autofluorescence for untreated and unexposed cells (CTRL), treated with punicalagin without UVA irradiation (CTRL + PUN), untreated and exposed to UVA for 2 h (UVA 2 h) and pretreated and exposed to UVA (UVA 2 h + PUN). Pixel colours range from dark purple (low levels of NADH) to yellow (high levels of NADH) according to the color bar reported with the images. The scale bar is 10 μm. (B) The bar graph represents the quantification of intracellular levels of NADH, reported as mean $\pm$ SD on the y-axis (n = 15 cells). Values were normalised to CTRL (mean NADH = 1.0). **p < 0.01 (control untreated and unexposed vs. control unexposed and pretreated cells; control untreated and unexposed vs. 2 h exposed cells; control unexposed and pretreated vs. 2 h exposed and pretreated cells); ****p < 0.0001 (2 h exposed untreated vs. 2 h exposed and pretreated cells) with t-test. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)