Fig. 2

Cellular reducing equivalents are increased in cells exposed to “diabetic” glucose levels and a range of cellular insults. a Statistically significant increases in cellular reducing equivalents are seen in the presence of 25mM glucose after exposure to intense light at all time points between 2 and 6 h when compared to a 5mM environment. The greatest change occurred at 5 h, with 19.0 % ± 2.0 % of control reduced formazan dye levels in 5mM glucose and 72.0 % ± 8.0 % in 25mM glucose (P < 0.001). b Exposure of cells to oxidative stress in the form of H₂O₂ for 2 h showed a dose dependent decrease in cellular reducing equivalents in both glucose levels, however excess glucose was associated with higher levels of cellular reducing equivalents in 661W cells at all concentrations of H₂O₂ between 1 and 10mM. After exposure to 5mM H₂O₂, reduced dye density was 16.5 % ± 0.1 % of untreated controls in “non-diabetic” conditions, and 22.7 % ± 3 % in “diabetic” conditions (P < 0.01). c Staurosporine, an inducer of apoptosis, also showed a dose dependent decrease in cellular reducing equivalents in both glucose environments, but a 25mM glucose environment was associated with greater cellular reducing equivalents at all concentrations of staurosporine between 10 and 400nM. When exposed to 100nM staurosporine, reduced dye density in cells exposed to 5mM glucose was 17.0 % ± 3 % of controls, whereas in 25mM glucose reduced dye density was 27 % ± 2 % of controls (P < 0.01). Unstressed cells did not show any significant difference in reduced formazan dye production when exposed to different levels of environmental glucose in any of the experiments. * indicate P < 0.05 between cells treated in the presence of 5mM and25 mM glucose