Curcumin combined with red united blue light induced apoptosis in HaCaT cells.

(A) Flow cytometric analysis of HaCaT cells without any treatment. (B)-(E) Flow cytometric analysis of HaCaT cells which were pre-incubated with curcumin (2.5 μM) for 2 h and then protected from light or separately irradiated with blue light and two combinations of blue and red light.(F) The apoptotic rate of cells was measured by the percentage of early apoptotic cells added late apoptotic cells. a, b, c and d represent normal cells, early apoptotic cells, late apoptotic cells and dead cells, respectively. Bars with different characters are statistically different at p<0.05(*) or p<0.01(**) level. All images shown are representative of three independent experiments.